diff --git a/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResult.java b/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResult.java
index cb2ab97c968..fcc55519ca0 100644
--- a/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResult.java
+++ b/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResult.java
@@ -8,7 +8,7 @@ public interface QueryResult<AggregatedType> extends Serializable {
     int getRetrievedDataAmount();
     public int getFilteredDataAmount();
     public double getCalculationTimeInSeconds();
-    
+    public boolean isEmpty();
 
     /**
      * @return a description what kind of results are contained.
diff --git a/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResultImpl.java b/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResultImpl.java
index 64fb8beaf1d..eee56c0741d 100644
--- a/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResultImpl.java
+++ b/java/com.sap.sailing.datamining/src/com/sap/sailing/datamining/shared/QueryResultImpl.java
@@ -11,8 +11,8 @@ public class QueryResultImpl<AggregatedType> implements QueryResult<AggregatedTy
     private long calculationTimeInNanos;
 
     private String resultSignifier;
-	private Unit unit;
-	private int valueDecimals;
+    private Unit unit;
+    private int valueDecimals;
 	
     private Map<GroupKey, AggregatedType> results;
     
@@ -50,6 +50,11 @@ public class QueryResultImpl<AggregatedType> implements QueryResult<AggregatedTy
         this.calculationTimeInNanos = calculationTimeInNanos;
     }
 
+    @Override
+    public boolean isEmpty() {
+        return results.isEmpty();
+    }
+
     @Override
     public String getResultSignifier() {
         return resultSignifier;
diff --git a/java/com.sap.sailing.gwt.ui/DataMining.css b/java/com.sap.sailing.gwt.ui/DataMining.css
index 899bf39ab6e..5854e646774 100644
--- a/java/com.sap.sailing.gwt.ui/DataMining.css
+++ b/java/com.sap.sailing.gwt.ui/DataMining.css
@@ -167,7 +167,7 @@ input.magnifier {
     height: 70px;
     margin: 0 auto;
     padding: 49px 0 0 80px;
-    width: 300px;
+    width: 400px;
     color: #7c7c7c;
 	background: url(images/important-message.png) left center no-repeat;
 }
\ No newline at end of file
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.java
index 038f87f98c1..18efccff5c7 100755
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.java
@@ -769,4 +769,9 @@ public interface StringMessages extends Messages {
     String queryResultsChartSubtitle(int retrievedDataAmount, int filteredDataAmount, double calculationTime);
     String noQuerySelected();
     String runAutomatically();
+    String noStatisticSelectedError();
+    String noCustomGrouperScriptTextError();
+    String noDimensionToGroupBySelectedError();
+    String noGrouperSelectedError();
+    String queryNotValidBecause();
 }
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.properties b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.properties
index 4e55a6f71e7..f87a64333ba 100755
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.properties
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages.properties
@@ -762,4 +762,9 @@ groupBy=Group by
 statisticToCalculate=Calculate statistic
 queryResultsChartSubtitle=Worked through {1}/{0} data entries in {2} seconds
 noQuerySelected=No query selected
-runAutomatically=Run automatically
\ No newline at end of file
+runAutomatically=Run automatically
+noStatisticSelectedError=No statistic to calculate is selected
+noCustomGrouperScriptTextError=The grouper script is empty
+noDimensionToGroupBySelectedError=No dimension to group by is selected
+noGrouperSelectedError=No grouper type is selected
+queryNotValidBecause=No query possible, because
\ No newline at end of file
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages_de.properties b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages_de.properties
index bae9aa7e842..9c68537c85c 100755
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages_de.properties
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/client/StringMessages_de.properties
@@ -758,4 +758,9 @@ groupBy=Gruppieren nach
 statisticToCalculate=Berechne Kennzahl
 queryResultsChartSubtitle=Es wurden {1}/{0} Datensätze in {2} Sekunden verarbeitet
 noQuerySelected=Keine Abfrage ausgewählt
-runAutomatically=Automatisch ausführen
\ No newline at end of file
+runAutomatically=Automatisch ausführen
+noStatisticSelectedError=Keine zu berechnende Kennzahl ausgewählt ist
+noCustomGrouperScriptTextError=Das Grouper-Skript leer ist
+noDimensionToGroupBySelectedError=Keine Gruppierungs-Dimension ausgewählt ist
+noGrouperSelectedError=Kein Gruppierungs-Typ ausgewählt ist
+queryNotValidBecause=Keine Datenabfrage möglich, da
\ No newline at end of file
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractQueryComponentsProvider.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractQueryComponentsProvider.java
index 6ce141c1388..1513ae5df52 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractQueryComponentsProvider.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractQueryComponentsProvider.java
@@ -1,5 +1,7 @@
 package com.sap.sailing.gwt.ui.datamining;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -25,25 +27,34 @@ public abstract class AbstractQueryComponentsProvider<DimensionType> extends Flo
 
         listeners = new HashSet<QueryComponentsChangedListener<DimensionType>>();
     }
-
+    
     @Override
-    public boolean areComponentsValid() {
-        return isGrouperValid() && isStatisticToCalculateValid() && isAggregatorValid();
+    public Iterable<String> validateComponents() {
+        Collection<String> errorMessages = new ArrayList<String>();
+        
+        String grouperError = validateGrouper();
+        if (grouperError != null && !grouperError.isEmpty()) {
+            errorMessages.add(grouperError);
+        }
+        
+        String statisticError = validateStatisticAndAggregator();
+        if (statisticError != null && !statisticError.isEmpty()) {
+            errorMessages.add(statisticError);
+        }
+        
+        return errorMessages;
     }
 
-    private boolean isAggregatorValid() {
-        return getAggregatorType() != null;
-    }
-
-    private boolean isStatisticToCalculateValid() {
-        return getStatisticToCalculate() != null;
-    }
-
-    private boolean isGrouperValid() {
-        ValidateGrouper: switch (getGrouperType()) {
+    private String validateGrouper() {
+        GrouperType grouper = getGrouperType();
+        if (grouper == null) {
+            return stringMessages.noGrouperSelectedError();
+        }
+        
+        ValidateGrouper: switch (grouper) {
         case Custom:
             if (getCustomGrouperScriptText().isEmpty()) {
-                return false;
+                return stringMessages.noCustomGrouperScriptTextError();
             }
             break;
         case Dimensions:
@@ -52,14 +63,20 @@ public abstract class AbstractQueryComponentsProvider<DimensionType> extends Flo
                     break ValidateGrouper;
                 }
             }
-            return false;
+            return stringMessages.noDimensionToGroupBySelectedError();
         default:
-            return false;
+            return stringMessages.noGrouperSelectedError();
         }
 
-        return true;
+        return null;
     }
 
+    private String validateStatisticAndAggregator() {
+        return getStatisticAndAggregatorType() == null ? stringMessages.noStatisticSelectedError() : null;
+    }
+
+    protected abstract StatisticAndAggregatorType getStatisticAndAggregatorType();
+
     @Override
     public void addListener(QueryComponentsChangedListener<DimensionType> listener) {
         listeners.add(listener);
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractResultsPanel.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractResultsPanel.java
index b10d568a038..f094cb62d0a 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractResultsPanel.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/AbstractResultsPanel.java
@@ -23,45 +23,48 @@ public abstract class AbstractResultsPanel<DimensionType, ResultType> extends Fl
     private QueryComponentsProvider<DimensionType> queryComponentsProvider;
 
     private Label queryStatusLabel;
-    private ResultsPresentator<ResultType> presentator;
+    private ResultsPresenter<ResultType> presenter;
 
     private Button runQueryButton;
 
     public AbstractResultsPanel(StringMessages stringMessages, SailingServiceAsync sailingService,
-            ErrorReporter errorReporter, QueryComponentsProvider<DimensionType> queryComponentsProvider, ResultsPresentator<ResultType> presentator) {
+            ErrorReporter errorReporter, QueryComponentsProvider<DimensionType> queryComponentsProvider, ResultsPresenter<ResultType> presenter) {
         super();
         this.stringMessages = stringMessages;
         this.sailingService = sailingService;
         this.errorReporter = errorReporter;
         this.queryComponentsProvider = queryComponentsProvider;
+        this.presenter = presenter;
         
         add(createFunctionsPanel());
-        this.presentator = presentator;
-        add(this.presentator.getWidget());
+        add(this.presenter.getWidget());
+        runQuery();
     }
-    
+
     @Override
     public void queryComponentsChanged(QueryComponentsProvider<DimensionType> componentsProvider) {
-    	if (componentsProvider.areComponentsValid()) {
-            runQuery();
-        } else {
-            //TODO Display error message
-        }
+        runQuery();
     }
 
     private void runQuery() {
-        queryStatusLabel.setText(" | " + stringMessages.running());
-        sendServerRequest(new AsyncCallback<QueryResult<ResultType>>() {
-            @Override
-            public void onFailure(Throwable caught) {
-                errorReporter.reportError("Error running the query: " + caught.getMessage());
-            }
-            @Override
-            public void onSuccess(QueryResult<ResultType> result) {
-                queryStatusLabel.setText(" | " + stringMessages.done());
-                presentator.showResult(result);
-            }
-        });
+        Iterable<String> errorMessages = queryComponentsProvider.validateComponents();
+        if (errorMessages == null || !errorMessages.iterator().hasNext()) {
+            queryStatusLabel.setText(" | " + stringMessages.running());
+            sendServerRequest(new AsyncCallback<QueryResult<ResultType>>() {
+                @Override
+                public void onFailure(Throwable caught) {
+                    errorReporter.reportError("Error running the query: " + caught.getMessage());
+                }
+
+                @Override
+                public void onSuccess(QueryResult<ResultType> result) {
+                    queryStatusLabel.setText(" | " + stringMessages.done());
+                    presenter.showResult(result);
+                }
+            });
+        } else {
+            presenter.showError(stringMessages.queryNotValidBecause(), errorMessages);
+        }
     }
 
     protected abstract void sendServerRequest(AsyncCallback<QueryResult<ResultType>> asyncCallback);
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/DataMiningPanel.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/DataMiningPanel.java
index 8d8c825b228..8924738c57e 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/DataMiningPanel.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/DataMiningPanel.java
@@ -12,7 +12,7 @@ public class DataMiningPanel extends FlowPanel {
         GPSFixQueryComponentsPanel selectionPanel = new GPSFixQueryComponentsPanel(stringMessages, sailingService, errorReporter);
         this.add(selectionPanel);
         
-        ResultsPresentator<Number> resultsChart = new ResultsChart(stringMessages);
+        ResultsPresenter<Number> resultsChart = new ResultsChart(stringMessages);
         GPSFixResultsPanel queryPanel = new GPSFixResultsPanel(stringMessages, sailingService, errorReporter, selectionPanel, resultsChart);
         this.add(queryPanel);
         
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixQueryComponentsPanel.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixQueryComponentsPanel.java
index c948d1221c5..2013f28b386 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixQueryComponentsPanel.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixQueryComponentsPanel.java
@@ -112,6 +112,11 @@ public class GPSFixQueryComponentsPanel extends AbstractQueryComponentsProvider<
         return dimensionsToGroupBy;
     }
 
+    @Override
+    protected StatisticAndAggregatorType getStatisticAndAggregatorType() {
+        return statisticsListBox.getValue();
+    }
+
     @Override
     public StatisticType getStatisticToCalculate() {
         return statisticsListBox.getValue().getStatisticType();
@@ -266,13 +271,15 @@ public class GPSFixQueryComponentsPanel extends AbstractQueryComponentsProvider<
         grouperTypeListBox.addValueChangeHandler(new ValueChangeHandler<GrouperType>() {
             @Override
             public void onValueChange(ValueChangeEvent<GrouperType> event) {
-                switch (event.getValue()) {
-                case Custom:
-                    groupByOptionsPanel.showWidget(1);
-                    break;
-                case Dimensions:
-                    groupByOptionsPanel.showWidget(0);
-                    break;
+                if (event.getValue() != null) {
+                    switch (event.getValue()) {
+                    case Custom:
+                        groupByOptionsPanel.showWidget(1);
+                        break;
+                    case Dimensions:
+                        groupByOptionsPanel.showWidget(0);
+                        break;
+                    }
                 }
                 notifyQueryComponentsChanged();
             }
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixResultsPanel.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixResultsPanel.java
index 1cb25950c8a..ca52492cfbc 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixResultsPanel.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/GPSFixResultsPanel.java
@@ -17,8 +17,8 @@ import com.sap.sailing.gwt.ui.datamining.QueryComponentsProvider.GrouperType;
 public class GPSFixResultsPanel extends AbstractResultsPanel<SharedDimensions.GPSFix, Number> {
 
     public GPSFixResultsPanel(StringMessages stringMessages, SailingServiceAsync sailingService,
-            ErrorReporter errorReporter, QueryComponentsProvider<SharedDimensions.GPSFix> queryComponentsProvider, ResultsPresentator<Number> presentator) {
-        super(stringMessages, sailingService, errorReporter, queryComponentsProvider, presentator);
+            ErrorReporter errorReporter, QueryComponentsProvider<SharedDimensions.GPSFix> queryComponentsProvider, ResultsPresenter<Number> presenter) {
+        super(stringMessages, sailingService, errorReporter, queryComponentsProvider, presenter);
     }
 
     @Override
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/QueryComponentsProvider.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/QueryComponentsProvider.java
index ad2b7a10ea3..73b863db3f9 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/QueryComponentsProvider.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/QueryComponentsProvider.java
@@ -10,7 +10,7 @@ public interface QueryComponentsProvider<DimensionType> {
     
     public enum GrouperType { Dimensions, Custom }
 
-    public boolean areComponentsValid();
+    public Iterable<String> validateComponents();
 
     public Map<DimensionType, Collection<?>> getSelection();
 
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsChart.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsChart.java
index 2bf00f7f598..04d57b1b388 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsChart.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsChart.java
@@ -20,7 +20,7 @@ import org.moxieapps.gwt.highcharts.client.labels.AxisLabelsFormatter;
 import org.moxieapps.gwt.highcharts.client.labels.XAxisLabels;
 import org.moxieapps.gwt.highcharts.client.labels.YAxisLabels;
 
-import com.google.gwt.user.client.ui.Label;
+import com.google.gwt.user.client.ui.HTML;
 import com.google.gwt.user.client.ui.RequiresResize;
 import com.google.gwt.user.client.ui.SimplePanel;
 import com.google.gwt.user.client.ui.Widget;
@@ -28,7 +28,7 @@ import com.sap.sailing.datamining.shared.GroupKey;
 import com.sap.sailing.datamining.shared.QueryResult;
 import com.sap.sailing.gwt.ui.client.StringMessages;
 
-public class ResultsChart implements ResultsPresentator<Number>, RequiresResize {
+public class ResultsChart implements ResultsPresenter<Number>, RequiresResize {
 
     private StringMessages stringMessages;
     private SimplePanel mainPanel;
@@ -39,37 +39,56 @@ public class ResultsChart implements ResultsPresentator<Number>, RequiresResize
     private Map<GroupKey, Integer> mainKeyToValueMap;
     private Map<Integer, GroupKey> valueToGroupKeyMap;
 
-    private Label noQuerySelectedLabel;
+    private HTML errorLabel;
 
     public ResultsChart(StringMessages stringMessages) {
         super();
         this.stringMessages = stringMessages;
         mainPanel = new SimplePanel();
         series = new HashMap<GroupKey, Series>();
-        noQuerySelectedLabel = new Label(this.stringMessages.noQuerySelected() + ".");
-        noQuerySelectedLabel.setStyleName("chart-importantMessage");
+        errorLabel = new HTML();
+        errorLabel.setStyleName("chart-importantMessage");
 
         createChart();
-        mainPanel.setWidget(noQuerySelectedLabel);
+        mainPanel.setWidget(chart);
+    }
+    
+    @Override
+    public void showError(String error) {
+        errorLabel.setHTML(error);
+        mainPanel.setWidget(errorLabel);
+    }
+    
+    @Override
+    public void showError(String mainError, Iterable<String> detailedErrors) {
+        StringBuilder errorBuilder = new StringBuilder(mainError + ":<br /><ul>");
+        for (String detailedError : detailedErrors) {
+            errorBuilder.append("<li>" + detailedError + "</li>");
+        }
+        errorBuilder.append("</ul>");
+        showError(errorBuilder.toString());
     }
 
     @Override
     public void showResult(QueryResult<Number> result) {
-        reset();
-
-        updateYAxisLabels(result);
-        updateChartSubtitleAndSetChartAsWidget(result);
-
-        List<GroupKey> sortedKeys = getSortedKeysFrom(result);
-        buildGroupKeyValueMaps(sortedKeys);
-
-        if (resultHasComplexKeys(result)) {
-            displayComplexResult(result, sortedKeys);
+        if (!result.isEmpty()) {
+            resetChart();
+            
+            updateYAxisLabels(result);
+            updateChartSubtitleAndSetChartAsWidget(result);
+            
+            List<GroupKey> sortedKeys = getSortedKeysFrom(result);
+            buildGroupKeyValueMaps(sortedKeys);
+            if (resultHasComplexKeys(result)) {
+                displayComplexResult(result, sortedKeys);
+            } else {
+                displaySimpleResult(result, sortedKeys);
+            }
+            
+            chart.redraw();
         } else {
-            displaySimpleResult(result, sortedKeys);
+            showError(stringMessages.noDataFound() + ".");
         }
-
-        chart.redraw();
     }
 
     private void updateYAxisLabels(QueryResult<? extends Number> result) {
@@ -152,7 +171,7 @@ public class ResultsChart implements ResultsPresentator<Number>, RequiresResize
         return series.get(key);
     }
 
-    private void reset() {
+    private void resetChart() {
         chart.removeAllSeries(false);
         series = new HashMap<GroupKey, Series>();
     }
diff --git a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsPresentator.java b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsPresenter.java
similarity index 59%
rename from java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsPresentator.java
rename to java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsPresenter.java
index e53d5bdf6d1..5f25d94c520 100644
--- a/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsPresentator.java
+++ b/java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/datamining/ResultsPresenter.java
@@ -3,10 +3,13 @@ package com.sap.sailing.gwt.ui.datamining;
 import com.google.gwt.user.client.ui.Widget;
 import com.sap.sailing.datamining.shared.QueryResult;
 
-public interface ResultsPresentator<ResultType> {
+public interface ResultsPresenter<ResultType> {
+
+    public Widget getWidget();
     
     public void showResult(QueryResult<ResultType> result);
 
-    public Widget getWidget();
+    public void showError(String error);
+    public void showError(String mainError, Iterable<String> detailedErrors);
 
 }