The problem:
In a Windows XP workstation, after joining the Windows 2003 Domain you can log on to the domain, but when you try to add a user from the domain as local administrator, the Domain name does not appear in the Location box.
Solution:
The problem usually is the DNS settings on the workstation's network card.
Change the current DNS IP Address into the server's IP Address and reboot the client machine.
Now try again to add the domain user.
When you finish, restore the original DNS settings.
