Can't access admin after upgrade - down for maintenance

[KlingstedtBrothers]

Hello,
I recently upgraded from 1.3.8a to 1.5.1. Before doing so I took the site down for maintenance. After uploading the files, and running the installer everything seemed to complete without issue. I cleared my active tokens, cache, and cookies from my browser. Upon going to the /admin folder, I received an error telling me to rename the folder. I did. When I tried to access the folder, I am automatically redirected to the home page of the front end, with the "Down For Maintenance" line.

No matter what I do, I'm redirected to the home page as the site is down for maintenance. I can't log-in to the site, to turn off the maintenance setting, nor access the back end in any way.

Homepage Notification: NOTICE: The website is currently Down For Maintenance to the public
Admin Error: Warning: You cannot access the admin until you have renamed the admin folder.
After renaming admin: NOTICE: The website is currently Down For Maintenance to the public

Any help would be appreciated.

[DrByte]

Sounds like you've got an old-style admin configure.php file, and when you renamed your admin folder you didn't also rename the references to it in your old-style configure.php file.