User account locked out of domain

I have a network that has 2 W2K Domain controllers, 3 Win 2003 server and a
bunch of XP and 2000 clients plus 3 Windows 98 computers. People that
regularly use the Windows 98 computers end up with their domain accounts
locked out 5-10 times a week when they are logged onto the Win98 computers
even if they are not doing anything.

When I check the Event Viewer on the domain controllers there is a few
entries that show a bad password attempt was made from the computer even
though it has been logged on. Also once the users account is locked, every
minute there are two more attempts to access the network and two locked out
events.