Looks like we're requesting the mapblocks for every agent - including

childagents. The infrastructure is not robust enough to handle it at 
this time - so ignore all the MapBlock requests for childagents.

OpenSim/Region/Environment/Scenes/Scene.cs

@@ -936,9 +936,12 @@ namespace OpenSim.Region.Environment.Scenes
         /// <param name="maxX"></param>
         /// <param name="maxY"></param>
         public void RequestMapBlocks(IClientAPI remoteClient, int minX, int minY, int maxX, int maxY)
+        {
+            if(!m_scenePresences[remoteClient.AgentId].IsChildAgent)
             {
                 m_sceneGridService.RequestMapBlocks(remoteClient, minX, minY, maxX, maxX);
             }
+        }
 
         /// <summary>
         ///