Can't login or register

Hello,

I’ve just installed WPBB on my website : http://www.caraporters.fr/forum/

It seems that I can’t register (either with or without Facebook). My website users can’t even login with their WP username.

Moreover, I don’t know how to post as a guest. Yet I enabled guest permissions.

Could you please help me?
Thanks

http://wordpress.org/plugins/wp-bulletin-board/