Problem with registrations

Hi. I have a problem with new users registration.
A friend of mine is trying to register, but whatever user name he uses - it always says "The user name is already taken", but I don't have any other users - it's only me. And my friend, who is still trying to register. How could I fix this?

General>Forum>Security
Unauthorize subscriptions made with the most commonly used spam usernames. : No
Save.

By choosing this option, please note that you are giving a gateway for spam usernames to be registered on your forum.

I forgot to say that I use phpBB2, it still matters. But the problem is solved. Thanks.


Edit: Oh, now I see I have a special field on my profile for phpBB2/3 or IPB.

Thanks again.