I have a site that is Windows AD (NTLM) only (Claims Based). I then "extended' that site and created an FBA Site (Internet Zone).
When I try o Approve a Membership request (by accessing the AD site), I get a "401 Access Denied" error when the "XsilCompiled.Load()" tried to load the MembershipApproved.xslt file. Although, I can type the path in the browser and it opens fine.
I decided to use ProcessMonitor to see what is going on. Right when it tries to open that "xslt" file, it tries to create a "web.config" file (or, maybe it is trying to open one, I am not sure). But the weird part, is it tries to open it in the same path as the "xslt" file (actually, it tries to treat the "xslt" file as a "directory").
Check out the Event from Process Monitor:
Date & Time: 3/13/2012 2:49:52 PM
Event Class: File System
Result: PATH NOT FOUND
Path: C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\template\layouts\FBA\emails\MembershipApproved.xslt\web.config
Desired Access: Read Attributes
Options: Open Reparse Point
ShareMode: Read, Write, Delete