We've recently started to upgrade our 5.1 sp8 servers to 6.5 sp6, we have
also been rolling out client 4.91 sp3

The problem is when the user does cntl-alt-del and password change, the
system comes back with the message

old password was not entered correctly, no passwords were changed.

I've been experimenting on my work station and can replicate this problem,
and I know I'm entering the correct old password.

I have no idea where to chase this problem down at, got any ideas?

our workstations are XP pro sp2