New Server 2003 (SP2) PDC- Cannot connect any clients to domain

I am configuring a new install of 2003 enterprise and I have DNS, DHCP, and Active Directory installed correctly (i think). None of the client machines (XP Pro) will connect. I can get the log on box, so I know they can “see” the domain, but then I immediatly get an error that says that they “can’t find the domain controller”.

Any thoughts?