Recently, one of my teammates installed ArcGis Server 9.3 on our fresh
SharePoint 2010 box, causing all sites to respond with
Unavailable. A quick inspection showed that the application pools have
stopped themselves, and the Windows application event log was spammed
Event ID: 2282 Source: Microsoft-Windows-IIS-W3SVC-WP Description: The Module DLL C:\Program Files\Common Files\Microsoft Shared\Web Server Extentions\14\isapi\owssvr.dll' could not be loaded due to a configuration problem. The current configuration only supports loading images built for a x86 processor architecture. The data field contains the error number...
After some investigation, I found out that the installation switched all
of the application pools into 32-bit mode, causing SharePoint's x64 dlls
to fail to load.
The solution I found - go over every pool in the IIS manager under
Application pools, open
advanced settings and set
Also, make sure you click
Set Application Pool Defaults and change the
settings there, for your future pools.