What a freakin’ error that is huh?  I kept getting it while trying to work on my 3-year old usability testing service.

Turns out it’s a conflict with Comatose and rails authentication.   Here’s the fix:

http://groups.google.com/group/comatose-plugin/browse_thread/thread/284a4a6698a6d9/f698dc284eb1451c?lnk=gst&q=A+copy+of+AuthenticatedSystem+has+been+removed+from+the+module+tree+but+is+still+active!#f698dc284eb1451c

Add ‘unloadable’ to line 3 of  comatose_admin_controller.rb


# The controller for serving cms content...