There is an IP address problem. Disconnect the Win98 from the network, boot up and remove any static IP's configured on it or check to find that IP being used by another device. This error indicated that the IP this machine has or is trying to use is already being used.

Someone had pulled the cables from the switch box and replugged them in a different order. One device requires a fixed IP address. For some reason when I rebooted the router and switch box it did not clear the routing tables. My router is configured to only allow 5 IP addresses so when I turned the laptop on the only IP available was the already used Fixed IP. I sorted out the cables, powered computers, switch, router and modem down and then rebooted everything and it all worked.

Turns out the PCMCIA card itself must have JUST gone bad. Worked prior to reinstall, but having swapped with another 3COM 10/100 LAN PC Card (fe574BT) card, it now works.

If this occurs with the NET PASSWORD command it may be a problem contacting the primary domain controller (PDC). When the NET PASSWORD command is used on a Windows 95/98 computer, the computer incorrectly attempts to resolve a NetBIOS domainname[1D] entry, rather than the appropriate domainname[1B] entry.

RESOLUTION
To work around this problem, change the syntax of the NET PASSWORD command. For example, at a command prompt type the following command net password \\servername username oldpassword newpassword See:
Windows XP Network Troubleshooting
Errors by the Number at PC Cruiser