Peculiar ASP.NET Error Message

This is displayed as a client message ("Error on page.") in the status bar. I think at this point, the app is us开发者_运维技巧ing some kind of AJAX callback in response to a login button.

Trying to deploy on a new Windows Server 2008 testbed (runs fine in debugger and has been deployed on Windows Server 2003, but we're trying to upgrade our testbed and production images for future installations.)

Where do I go next to track down the root cause?

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB6.6; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; MDDR; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; MS-RTC LM 8; AskTbARS/5.11.3.15590)
Timestamp: Tue, 22 Mar 2011 18:24:57 UTC


Message: Sys.WebForms.PageRequestManagerServerErrorException: The source was not found, but some or all event logs could not be searched.  Inaccessible logs: Security.
Line: 5
Char: 62099
Code: 0
URI: http://XXX.XXX.XXX.XXX/ScriptResource.axd?d=h-4WZuFBCcT-1QOz27ZRxMnCrM1dJDc_fETsNUPAfsPgng_3pAoC80eScNiAc9AAVaTQPonQz7cMCVz6SHzZIJ0Tvj-YmVHBRaokQGWQIKRz7KO0y6B7UKgccbT4YFzWqhNPS7kUsVnHQX2F9zBJAK9qeEI1&t=40fa519

Just a shot in the dark, but it might be that the ASP.NET AJAX resources aren't loaded on the new server. I vaguely remember having the same issue a year or so ago and, IIRC, I had to load the .NET Framework 2.0 AJAX libraries on the server.

This is just a guess. Maybe it's being run on IIS7 now, and the configuration is different for IIS7. If you are just trying to get it working, in IIS7 server settings, trying switching your application pool to from Integrated Mode to Classic Mode.