Error Message:
Attention important additional information because of current Web.config configuration:
There exists the possibility that this exception happened because of a Session-Timeout or an App-Pool recycling.

This is an invalid webresource request. (System.Web)

     at System.Web.Handlers.AssemblyResourceLoader.System.Web.IHttpHandler.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)