Nate, do you have a **DONOTDELETE** user anywhere in the database. Before adding a new one try this query:
select U_Number from w3t_Users where U_Username='**DONOTDELETE**'
If you get a result back, just change that to #1. That would be the easiest way.
If you don't get a result, then yes you'll want to add a **DONOTDELETE** user as user #1. You'll want to give it some sort of random password and assign the U_Groups field to '-4-'