Can’t map to server – server not found?

I have 3 new IBM M-Pro workstations that will not allow me to map a drive to an NT server. These machines are not in a Domain.

when I map to \\IP\share, it comes back “Server can not be found”

All the other Win2000 machines I have (notebooks,desktops) will map to the NT server no problem.

All the Network connection, IP, Client etc settings all appear to be the same. There must be a setting somewhere I am missing or possibly a parameter for a component that causes it to time out before connecting to the server?