You may face this issue. Sometimes member computers running Windows XP/2000/2003 may not load roaming profile from a trusted domain.
They should be able to log as long as the following conditions are true:
1. DNS settings are incorrect as suggested on some of your client computers.
2. Workstation service is not running on client computer.
3. Server service is not running on server.
4. Roaming Profile Share is not shared on server.
5. Permissions are not shared properly.
6. All Users and Default Users folders in Documents and Settings are missing if this is the first time user is logging on to this computer.
7. IPC$ share is missing on Client computer or Server.
You can find the exact cause by enabling the User Profile Debugging:
Enable User Profile Logging. You will know the problem.