Index: lams_flash/src/central/flash/org/lamsfoundation/lams/authoring/DesignDataModel.as
===================================================================
diff -u -r6b04e69c42c1f73e069ecb5a735ff97c9f50a0a1 -r1d252c442d2a807f45abbc77f366c2952ce4c44d
--- lams_flash/src/central/flash/org/lamsfoundation/lams/authoring/DesignDataModel.as	(.../DesignDataModel.as)	(revision 6b04e69c42c1f73e069ecb5a735ff97c9f50a0a1)
+++ lams_flash/src/central/flash/org/lamsfoundation/lams/authoring/DesignDataModel.as	(.../DesignDataModel.as)	(revision 1d252c442d2a807f45abbc77f366c2952ce4c44d)
@@ -1428,6 +1428,10 @@
 		_branches = a;
 	}
 	
+	public function get groupings():Hashtable{
+		return _groupings;
+	}
+	
 	public function get branchMappings():Hashtable {
 		return _branchMappings;
 	}
Index: lams_flash/src/central/flash/org/lamsfoundation/lams/authoring/cv/Canvas.as
===================================================================
diff -u -rb3d9e6021b71dcb7f55a13a2508e80a21141baf9 -r1d252c442d2a807f45abbc77f366c2952ce4c44d
--- lams_flash/src/central/flash/org/lamsfoundation/lams/authoring/cv/Canvas.as	(.../Canvas.as)	(revision b3d9e6021b71dcb7f55a13a2508e80a21141baf9)
+++ lams_flash/src/central/flash/org/lamsfoundation/lams/authoring/cv/Canvas.as	(.../Canvas.as)	(revision 1d252c442d2a807f45abbc77f366c2952ce4c44d)
@@ -217,9 +217,17 @@
 			LFMessage.showMessageConfirm(Dictionary.getValue("redundant_branch_mappings_msg"), Proxy.create(_ddm, _ddm.removeRedundantBranchMappings, Proxy.create(this, saveDesignToServer, workspaceResultDTO)), null, Dictionary.getValue("al_continue"), null);
 		} else {
 			var dto:Object = _ddm.getDesignForSaving();
-			var callback:Function = Proxy.create(this,onStoreDesignResponse);
+			var groupingUIID:Number = null;
+			if((groupingUIID = validateGroupings()) != null) {
+				// return error message
+				Cursor.showCursor(Application.C_DEFAULT);
+				LFMessage.showMessageAlert('Group names must be unique. Please review the Grouping Activity: '' + _ddm.getGroupingActivityByGroupingUIID(groupingUIID).title + ''', null);
+				return false;
+			} else {
+				var callback:Function = Proxy.create(this,onStoreDesignResponse);
 				
-			Application.getInstance().getComms().sendAndReceive(dto,"servlet/authoring/storeLearningDesignDetails",callback,false);
+				Application.getInstance().getComms().sendAndReceive(dto,"servlet/authoring/storeLearningDesignDetails",callback,false);
+			}
 		}
 		
 		return true;
@@ -300,6 +308,30 @@
 		}
 	}
 	
+	public function validateGroupings():Number {
+		var keys:Array = _ddm.groupings.keys();
+		var currentGrouping:Grouping = null;
+		
+		for(var i=0; i<keys.length; i++) {
+			currentGrouping = _ddm.groupings.get(keys[i])
+			var groups:Array = currentGrouping.getGroups(_ddm);
+			groups.sortOn("groupName", Array.UNIQUESORT | Array.ASCENDING);
+			
+			var group:Group = null;
+			if(groups.length > 0)
+				group = groups[0];
+			
+			for(var j=1; j<groups.length; j++) {
+				if(group.groupName == groups[j].groupName)
+					return currentGrouping.groupingUIID;
+				else
+					group = groups[j];
+			}
+		}
+		
+		return null;
+	}
+	
 	/**
 	 * Called when a template activity is dropped onto the canvas
 	 * @usage