Strange XP behavior upon joining a domain

[James McVeigh]

HI,

I am banging my head against a wall trying to figure this
one out. I helped a friend create a domain last night
with a Windows 2003 server and had no isssues joining a
handful of machines to the new domain. Upon joining the
last machine to the domain, his local account (which has
admin rights on the box) on the machine suddenly wouldn't
work, acting as if his password was incorrect upon trying
to login.

I restored the machine to the previous days configuration
and tried again. This time I was able to login to his
local account after joining the domain, but as soon as I
actually logged into the domain and attempted to switch
users back to the local account....no workee again.

This one has me stumped and any help would be appreciated

Thanks in Advance!