Some users cannot authenticate on Win2K machines

We are running Samba 2.2.2 on an HP-UX 10.20 server with Windows 9x and
2K/XP clients.  All users are able to log on to any 9x machine, but only
some users can log onto the Windows 2K/XP machines.  The message for those
who cannot logon is the standard 'check username and password. make sure
capslock is not on', etc.  We have checked the logs, etc. and cannot kind a
disparity between those who can logon and those who cannot.  Please help
ASAP.  Thanks so much.

dave cava
Dairy Barn Stores