asp.net failed to run in dot net 4.0

Question

The website was developed in dot net 3.5 SP1 and running ok within dot net 3.5 SP1. But, after recompiled it into dot net 4.0 and changed the app pool to "integrated", it failed to run. The symptom is that the website was running ok for few minutes. Then, the following message will appear:

[NullReferenceException: Object reference not set to an instance of an object.]
System.Web.PipelineStepManager.ResumeSteps(Exception error) +197
System.Web.HttpApplication.BeginProcessRequestNotification(HttpContext context, AsyncCallback cb) +89
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +189

If we recycle the app pool, it will work for a few minutes and then same error appear.

Any help is appreciated.

Lau.

As a first step, could you use symchk from Debugging Tools for Windows to get hold of PDBs for System.Web so you can translate the +offset into line numbers, then you can get source from the Microsoft symbol servers to see exactly what's going on on those lines. But if you're lucky someone will have seen this before? — Rup
Try the ASP.NET 4.0 application pool instead, see if that makes any difference. — Brian Mains
Using WinDbg is the ultimate way, but be familiar with typical call stacks is much quicker :) — Lex Li

Lex Li Lex Li · Accepted Answer · 2011-02-21T13:42:31

From the call stack I think this exception was caused by a problematic HTTP module or handler.

You should be able to debug using Visual Studio or WinDbg.

asp.net failed to run in dot net 4.0

1 Answers