Unable to Join 2K3 Domain

I have recently set up Win 2k3 server running a small network of 4 workstations. (all XP pro).

Three of the WS’s joined the domain without a hitch but the fourth will not join. I just get the message:-

The following error occurred whilst attempting to join the domain “mydomain”. Access denied.

This WS had run on a Linux Domain previously. All the settings seem to be identical to the machines that joined with no probs.

Any suggestions would be welcomed!