Protocol Error 38

When attempting to log on to a win nt-4 server with either a win95-98 machine we sometimes get a small screen that says error 38 loading protocol 1.The computer name is already in use onthe network go to net hood and change computer name.This doesn’t happen every time or with every machine. Rebooting the domain server usually solves it for a while. Their are no duplicate names on network and changing computer name doesn’t help.Microsoft “guru’s” insist that there are duplicate names on the network.