Locked out from my site after setting authentication required

I was having a lot of problem using Black Board Theme, finaly fixed many of them, then set the option to required authentication and I’m now locked out of the site, and also the admin site.

I have full access from “behind the scene” (it’s on my server) but don’t know waht to change, either in the database,either in configuration files.

Some help would be welcomed.

Thanks