Windows Server 2003 Terminal server SP1

We have a Win 2003 setup as our Terminal server and its locked down pretty good with permissions. We tried to install SP1 on the server and it installed almost right to the end and then i got a access denied message and the service pack rolled back. Im not sure where to look to relax some permissions, i was logged in as the domain administrator and got the message, the domain admin is also a member of the local admins group also. Any help here would be great!

Thanks!