--- a/flys-client/src/main/java/de/intevation/flys/client/client/FLYS.java	Thu Jun 23 09:11:54 2011 +0000
+++ b/flys-client/src/main/java/de/intevation/flys/client/client/FLYS.java	Thu Jun 23 09:22:54 2011 +0000
@@ -2,14 +2,18 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 
 import com.google.gwt.core.client.EntryPoint;
 import com.google.gwt.core.client.GWT;
+import com.google.gwt.event.shared.UmbrellaException;
 import com.google.gwt.user.client.rpc.AsyncCallback;
 import com.google.gwt.user.client.ui.RootPanel;
 import com.google.gwt.xml.client.XMLParser;
 
 import com.smartgwt.client.util.SC;
+import com.smartgwt.client.widgets.Window;
+import com.smartgwt.client.widgets.HTMLPane;
 import com.smartgwt.client.widgets.layout.VLayout;
 import com.smartgwt.client.widgets.layout.HLayout;
 import com.smartgwt.client.widgets.events.CloseClickHandler;
@@ -100,6 +104,12 @@
     public void onModuleLoad() {
         openProjects = new ArrayList<String>();
 
+        GWT.setUncaughtExceptionHandler(new GWT.UncaughtExceptionHandler() {
+            public void onUncaughtException(Throwable e) {
+                showWarning(e);
+            }
+        });
+
         VLayout vertical = new VLayout();
         vertical.setLayoutMargin(1);
         vertical.setWidth100();
@@ -153,6 +163,40 @@
     }
 
 
+    public void showWarning(Throwable e) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("<tt>");
+
+        if (e instanceof UmbrellaException) {
+            UmbrellaException u = (UmbrellaException) e;
+            Set<Throwable> throwables = u.getCauses();
+
+            for (Throwable t: throwables) {
+                sb.append(t.getLocalizedMessage());
+                sb.append("<br>");
+            }
+        }
+        else {
+            sb.append(e.getLocalizedMessage());
+        }
+
+        sb.append("</tt>");
+
+        Window w = new Window();
+        w.setTitle(MSG.unexpected_exception());
+        w.setWidth(550);
+        w.setHeight(300);
+        w.centerInPage();
+        w.setCanDragResize(true);
+
+        HTMLPane p = new HTMLPane();
+        p.setContents(sb.toString());
+
+        w.addItem(p);
+        w.show();
+    }
+
+
     /**
      * This method should be called at system start. It initialzes the client
      * configuration.