Slow saves in XP

My installation runs 2 servers, one NT4 SP6a and one Win2k, SP2. DNS is running on the Win2K server. The order of DNS servers in DHCP is first the 2 servers of our ISP and than the Win2K server. Our Win98 workstations are working with no problem, however SOME of our XP workstations are very slow to save WORD documents to the network, while having no problem saving to the workstation. Also, our script files execute very slowly on the XP workstations. Any idea why we are having the slow saves? Isour DNS set up correctly?