I'm having some strange problems with my fast user switching. When switching from one network user account to another, I sometimes get the error:

"You are unable to log in to the user account "%username% at this time"
"Logging in to the account failed because an error occured"

If I logoff the currently logged on user, the errored user can log on just fine!!

I did have this error some time ago when I had the OSX Server bound to AD, but this is not the case anymore.

OSX Server 10.4.11
OSX Client 10.5.8

Google doesn't know, can anyone help?