Had the same problem. Apparently 2003 takes users in general NT4 groups and puts them into "Guest" groups in the AD. My administrator account was in "everyone" and ended up in "Domain Guests". Guests are explicitly denied access to the certain event logs. It also made "Domain Guest" my primary group, and thus I had to correct that before I could remove the account from the guest group. Here's what I found from MS:
"Cause: Your account has been added to the Guests group on the target computer, and is also a member of the Administrators group.
Solution: Remove your account from the Guests group on the target computer:"
Hope that helps.