After trying a new Friendly URL provider, I have returned my site to it's previous web.config and dll set. I am however now getting a Object reference not set to an instance of an object error when clicking the Login link on all portals. My web.config was restored from a backup so I am sure it is a good working version, and I removed the dll from the bin directory.

The problem I am having in tackling this problem is that I cannot seem to get a stack trace for the exception. I just get a critical error has occured ! on the page. I looked at the EventLog table in my DB and can see the exceptions, but cannot see any detail or stack trace. Without being able to login I cannot see the Events module in the Admin. I also browsed the page on the server. Any ideas on config or otherwise that would allow me to see a stack trace to start narrowing down the problem?