Ok, Not that I'm usually the harse type, but seriously, I'm going completly rootless crazy over this mad error!

Once I'm starting it, I have no error at all with my MySQL installation (fresh installation). But the issue occur when I'm trying to install a script as phpBB, then I get this error aaaaaaall the way:
phpBB : Critical Error

Could not connect to the database
I'm growing furiously by this, please, I beg you, I'll give you a scooby snack, whatever, if you can solve this issue for me! :P