Object reference not set to an instance of an object.   at Microsoft.SharePoint.SPSite.PreinitializeServer(SPRequest request)
   at Microsoft.SharePoint.SPWeb.InitializeSPRequest()
   at Microsoft.SharePoint.SPWeb.EnsureSPRequest()
   at Microsoft.SharePoint.SPWeb.get_Request()
   at Microsoft.SharePoint.WebControls.SPControl.SPWebEnsureSPControl(HttpContext context)
   at Microsoft.SharePoint.WebControls.SPControl.GetContextWeb(HttpContext context)
   at Microsoft.SharePoint.ApplicationRuntime.BaseApplication.Application_PreRequestHandlerExecute(Object sender, EventArgs e)
   at Microsoft.SharePoint.ApplicationRuntime.SPRequestModule.PreRequestExecuteAppHandler(Object oSender, EventArgs ea)
   at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)