User stuck on Subscribe page

We had a problem with a user join, we've gone in and deleted the account before re-entering the info in the back end but when you try the users username and password we get the message:

"Completed: Thank you for joiningIt looks like you are already a member of our site. Thank you very much for your support.If you are at this page because you would like to create another account, then please log out first."

Unfortunately, this is the only message you get throughout the site and you cant access any of the other pages. Please help.

Ben

PS It's also happening to all registrations now ;-(