Completed a fresh installation on a CentOS box. Everything seems fine, and neither the Apache or mySQL logs are complaining or catching any errors, but when I try to log in for the first time as admin/admin, I'll see a dashboard-looking screen for half a second then get bounced back to index.php?logout. Infinite loop - can't break it.

Like I said, no errors or issues to speak of that I can find.

Where would I even start looking for something like this?