Win 98 client printer problem

We have all our Laser printers serviced by a Window 2000 server on LAN.
Currently we are experiencing problems with Windows 98 workstations not
being able to print to any network printer. However, all the Windows 2000
workstations works fine. When try to print from Windows 98 workstation, user
get error message saying there is not enough memory to write to printer port
and that printer will be set to offline. Does anyone have any idea what
could cause this problem? Thanks.

By the way, we happened to have an NT server that also configured to support
all the network printer. We switched all the Windows 98 users to NT server
as print server and they are able to print to network printers.

Any suggestions or tips are greatly appreciated.