Rails - Apr 2006 - Session-Problem: singleton can''t be dumped

Hello,

after having changed the session store from CGI::Session::DRbStore to 
CGI::Session::ActiveRecordStore, I keep getting an error which says:

singleton can''t be dumped

However, my session object is not a singleton.

Does anybody know what causes this error?

I can also post the full stack trace, if required.

Greetings

Michael Kastner