--- a/gnv/src/main/java/de/intevation/gnv/action/WMSAction.java	Fri Mar 19 12:42:08 2010 +0000
+++ b/gnv/src/main/java/de/intevation/gnv/action/WMSAction.java	Fri Mar 19 13:15:59 2010 +0000
@@ -11,7 +11,6 @@
 import org.apache.struts.action.ActionForm;
 import org.apache.struts.action.ActionForward;
 import org.apache.struts.action.ActionMapping;
-
 import org.w3c.dom.Document;
 
 import de.intevation.gnv.action.sessionmodel.DiagrammOptions;
@@ -121,8 +120,13 @@
             request.setAttribute("mapserver", mapserverPath);
             request.setAttribute("mapfile", mapfilePath);
             request.setAttribute("layer", layer);
-
-            return super.execute(mapping, form, request, response);
+            if (mapserverPath != null && 
+                mapfilePath != null   &&
+                layer != null){
+                return super.execute(mapping, form, request, response);
+            }else{
+                return super.getExceptionForward(mapping);
+            }
         }
         catch (Exception e) {
             logger.error(e, e);