>It might have something to do with your ExceptionObj ... are you sure it exists? Are you sure .InnerException exists?

Yes on both. What I was doing at one point is to save the exception object to a session variable, then call an error reporting ASPX page which retrieves it, and successfully does the ToString() and provides all the interesting information about the error that occurred, so I know that both the Exception and InnerException objects exist. I ended up doing this as I first started by calling the error reporting page and attempted to pass the value returned by ToString() as a parameter to the page, and the Application_Error method was choking on the ToString(). Then after I succeeded in getting the Exception object to the called page via the session variable, I figured that I might be able to get around this by calling the ToString() in a class (and also figured that a general-purpose ExceptionHandler was the way to go anyway), but it still causes a problem. Interesting that it doesn't cause a problem when it's called in the code-behind for a page launched from the Application_Error, huh?