[Zope] SQLSession Problem

Hi All, I'm using zope 2.1.6 with apache server on NT platform. and I had a problem with SQLSession. I tried to put in the '_force_new_session' flag whenever I called a session, so I can have a fresh SessionID. But I always got a error return with a message "TypeError". So I wonder if this is the correct way to call the session component : <dtml-call "Session('_force_new_session=1')"> Please help. Cheers Wai