SBS 2003 Installation problem

Hi all, I have been trying to install a new SBS 2003 server in an existing domain. The old DC is a 2000 SP4 server. I was able to run forestprep and domainprep successfully. I joined the new sbs server to the domain and successfully transfered all of the FSMO roles and the global catalogue as per the M$ technet article. Netdiag and dcdiag both come back with no errors. However now when i click on the link to continue the setup of SBS 2003 it gives me an error stating that i need to be a member of the domain admins, enterprise admins, and schema admins groups and will not continue. I have triple checked the admin account and i am a member of all of those groups. Has anyone seen this sort of problem before?