SBS 2003 from NT and Shares

I have a problem I hope someone can help with. We recently upgraged to SBS
2003 from NT4.0 sp6a. All of our workstations are XP pro machines. Most of
the xp systems seem fine, but I have a problem with 2. I set the shares on
them just like other xp pro machines and no one can see their shares. I can
see the computer in network neighborhood but when I click on it to access the
shares it says: "ZZZ is not accessible. You might not have permission to use
this network resource. Contact the administrator of thsi server to find out
if you have access permissions." It appears that everything is set. One other
note, the domain name was changed on the SBS 2003 server than what he NT box
had. The domain names were then changed on each of the xp pro workstations
and none of the shares were deleted or removed when the switch was made. If
you need more info please ask. Thanks.