Index: lams_central/src/java/org/lamsfoundation/lams/authoring/service/AuthoringService.java
===================================================================
diff -u -r79c858a92c17ab3ca404cab4a0cf6094254e68d5 -rfca7f5f4bc72061fa82b651377d299a76ed9d090
--- lams_central/src/java/org/lamsfoundation/lams/authoring/service/AuthoringService.java	(.../AuthoringService.java)	(revision 79c858a92c17ab3ca404cab4a0cf6094254e68d5)
+++ lams_central/src/java/org/lamsfoundation/lams/authoring/service/AuthoringService.java	(.../AuthoringService.java)	(revision fca7f5f4bc72061fa82b651377d299a76ed9d090)
@@ -234,17 +234,6 @@
 		}
 		return flashMessage.serializeMessage();
 	}	
-	/**
-	 * Checks whether the WDDX packet contains any invalid
-	 * "<null/>". It returns true if there exists any such null
-	 */
-	private boolean containsNulls(String packet)
-	{
-		if (packet.indexOf("<null />") != -1)
-			return true;
-		else
-			return false;
-	}
 	public String copyLearningDesign(Long originalDesignID,Integer copyType,
 									Integer userID, Integer workspaceFolderID)throws UserException, LearningDesignException, 
 											 							      WorkspaceFolderException, IOException{
@@ -420,12 +409,6 @@
 	public String storeLearningDesignDetails(String wddxPacket) throws Exception{
 		LearningDesignDTO learningDesignDTO = null;
 		
-		if(containsNulls(wddxPacket)){
-			flashMessage = new FlashMessage("storeLearningDesignDetails",
-											"WDDXPacket contains null",
-											FlashMessage.ERROR);
-			return flashMessage.serializeMessage();
-		}		
 		Hashtable table = (Hashtable)WDDXProcessor.deserialize(wddxPacket);
 		ObjectExtractor extractor = new ObjectExtractor(userDAO,learningDesignDAO,
 														activityDAO,workspaceFolderDAO,
@@ -514,12 +497,6 @@
 	 */
 	public String storeTheme(String wddxPacket) throws Exception {
 		
-		if(containsNulls(wddxPacket)){
-			flashMessage = new FlashMessage("storeTheme",
-											"WDDXPacket contains null",
-											FlashMessage.ERROR);
-			return flashMessage.serializeMessage();
-		}		
 		Hashtable table = (Hashtable)WDDXProcessor.deserialize(wddxPacket);
 		
 		CSSThemeDTO themeDTO = new CSSThemeDTO(table);
Index: lams_common/src/java/org/lamsfoundation/lams/web/servlet/AbstractStoreWDDXPacketServlet.java
===================================================================
diff -u -r21a2b87e69eac5b2bf9b38863e4637e25d35b773 -rfca7f5f4bc72061fa82b651377d299a76ed9d090
--- lams_common/src/java/org/lamsfoundation/lams/web/servlet/AbstractStoreWDDXPacketServlet.java	(.../AbstractStoreWDDXPacketServlet.java)	(revision 21a2b87e69eac5b2bf9b38863e4637e25d35b773)
+++ lams_common/src/java/org/lamsfoundation/lams/web/servlet/AbstractStoreWDDXPacketServlet.java	(.../AbstractStoreWDDXPacketServlet.java)	(revision fca7f5f4bc72061fa82b651377d299a76ed9d090)
@@ -91,6 +91,13 @@
 				log.debug("Request "+request.getRequestURI()+" received packet "+packet);
 			}
 
+			if(containsNulls(packet)){
+				FlashMessage flashMessage = new FlashMessage(getMessageKey(packet,request),
+												"WDDXPacket contains null",
+												FlashMessage.ERROR);
+				writer.write(flashMessage.serializeMessage());
+			}		
+
 			replyPacket = process(packet, request);
 
 			if ( log.isDebugEnabled() ) {
@@ -103,7 +110,7 @@
 			log.error(uri+" request triggered exception ",e);
 			
 			FlashMessage flashMessage = FlashMessage.getExceptionOccured(getMessageKey(packet,request),
-					e.getMessage()!=null?e.getMessage():"");
+					e.getMessage()!=null?e.getMessage():e.getClass().getName());
 			writer.write(flashMessage.serializeMessage());
 			return;
 		}
@@ -115,6 +122,18 @@
 	
 
 	/**
+	 * Checks whether the WDDX packet contains any invalid
+	 * "<null/>". It returns true if there exists any such null
+	 */
+	private boolean containsNulls(String packet)
+	{
+		if (packet.indexOf("<null />") != -1)
+			return true;
+		else
+			return false;
+	}
+
+	/**
 	 * Method to get the post body.
 	 * Retrieves the body of the post as binary data, and then converts back to a character stream.
 	 * The reason why we didn't use getReader() which retrieves the body of the post as character