On our MOSS Enterprise environment, we have a strange problem. From time to time, people get this error message when they try to create a new site collection or navigate to their mysite:
‘Could not load file or assembly 'Microsoft.SharePoint.ApplicationPages, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c' or one of its dependencies. Access is denied.’
The problem is fixed by updating the security of directory c:\inetpub\wwwroot\wss\virtualdirectories\[central admin folder]\ (for creating site collections) or c:\inetpub\wwwroot\wss\virtualdirectories\[mysite folder]\.
After a couple of hours or days, the problem returns and we have to update the security again. Has anyone else seen this behavior before ?