register always says “username already exists”

Hi All,

As of last night, when a user tries to register on my site, the registration goes through, and the user can login after; however, the page reloads and no matter what username and email I pick, it says that username and email are already taken.

You have to use the password ‘whiskers’ to view the site.

Thanks!

The page I need help with: [log in to see the link]