Thread was being aborted

This exception is throw by the call to Server.Transfer in order to halt the execution of the current method – exactly the same thing gets thrown if you do Response.Redirect.

The two choices you have are:

• Catch and rethrow the
  ThreadAbortException / reperform the
  Server.Transfer
• Make sure that you
  only do Server.Transfer in places
  where it wont be caught (recommended)

EDIT: Scratch that, http://support.microsoft.com/kb/312629 has a couple of other suggestions to try, but I still recommend #2 above.