samba - May 2007 - samba v2.2.3a - w2k-Users CAN change password, how to disable ?

Dear List, dear Samba-Users,

I've been assigned to service an old samba server (v2.2.3a) with 
smbpasswd-backend and some hundred w2k-PDC-users.

Now I stumbled over a small problem:

If windows-users change their passwords via the
"ctrl-alt-del"-dialogue
they are prompted an error that the domain is not available but the 
password is changed nonetheless.

The only solution I came across is to disable the button with the help 
of policies to the user profile.

Do You know of this error and have another solution for my problem?

Thanks in advance,

Martin Petersen

(Please excuse my poor grammar, reading English tech books doesn't teach 
the last skills :))