[Zope] Login problem

I'm using zope 2.6.2b5 and I'm having trouble logging on (using exUserFolder). After entering user name, password, and hitting submit - the screen redirects back to the login screen with no error statement about bad user name or password. I'm only getting the problem on one of my installs - it used to work just fine but suddenly stopped! I don't think anything has changed on the machine. Anyone got any ideas? Many thanks Liz ________________________________________________________________ Sent via the WebMail system at rcsltd.co.uk