One way is to delete base/admin.dat
That will reset all your admin stuff to default.
You can also do !setlevel example 0, then !setlevel example 5 (from your server console)
If you're wanting the same admin account on a different computer, you'll need to copy the qkey file.
For Linux it's located at ~/.tremulous/qkey
Fun title, but I've seen help tickets that were far worst.