Are you using the Super Admin account?
It's advised you make your own Admin account rather than the one you first create within Server 2003.
I just reinsalled xp pro sp2. I am somewhat experienced with xp and server 2003, not a complete noob. For some reason, after about 2 days now, i somehow lose my admin privileges. Im logged in as the admin, and i check the user accounts and it says the lol "admin" user is in the admin group. Basically, I KNOW IM LOGGED IN AS THE ADMIN!!! If its not enough that im logged in as the admin, i created anoter user acct with admin privileges!!! The only reason i believe i lost the privileges is somehow, i can't install most of the programs i have saved. It stops and says "must be logged in as admin" for almost all of my programs now. I cant even save a url as my "home" in the internet options. I can't install World of warcraft. I need to be logged in as the admin. But i AM!!! Can you somehow lose admin privileges even with the admin acct(login)?? This is driving me crazy. I even created a domain from a 2003 server machine, added the problematic computer to the domain and logged in as the domain admin, i still can't install these programs, i need to be logged in as the admin, WHAT IS GOIN ON??? Any help would be appreciated guys. I can't take this anymore, let me know if you need any more info.