My login worked for my upgrade and I'm user 4 with admin rights. The Admin account has never been used on my boards. So I don't think it's looking for user 1.
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.