Ajax.dll creating error

I am using ASP.Net 2.0 With C# for my chatting application. I am also using Ajax.dll in my application. To get the latest chat updates I am calling a method through ajax after every 6 seconds.It is working fine. But I am Continuously getting the following error :-

Object reference not set to an instance of an object. at Ajax.AjaxRequestProcessor.Run() at Ajax.AjaxHandler.ProcessRequest(HttpContext context) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously )

I am getting this error in my mail box continuously by a email sending code. This email sending code is written in global.asax's Application_Error section. 开发者_StackOverflowThere is no problem with this mail sending code. Whenever any kind of application error occurs it prompts me. But the above mentioned error is such an error i can't solve it yet. Please help me in this regard.

---

This happens if you request an .ashx (ajax handler URL) that references a missing or non-existent DLL (not found in your web app's bin folder, or bad class name).

You can reproduce it using a bogus url:

http://hostname/webappname/ajax/BogusNameSpace.BogusClassName,BogusNameSpace.ashx