Close was being called to early on the Memory stream.

OpenSim/Framework/Servers/HttpServer/AsynchronousRestObjectRequester.cs

@@ -82,7 +82,6 @@ namespace OpenSim.Framework.Servers.HttpServer
                     serializer.Serialize(writer, obj);
                     writer.Flush();
                 }
-                buffer.Close();
 
                 int length = (int) buffer.Length;
                 request.ContentLength = length;
@@ -109,13 +108,16 @@ namespace OpenSim.Framework.Servers.HttpServer
                         }
                         finally
                         {
+                            buffer.Close();
                             respStream.Close();
                             response.Close();
                         }
 
                         action(deserial);
+
                     }, null);
                 }, null);
+
                 
                 return;
             }