i fixed it, it was something in setup_options.php... the email field (i added it again) were showing the user's ip, not it's email... i changed it and signature worked fine.
but, now i have other problem, avatars arent showed in the forums, but they are showed at the users preferences, i checked for bb_function_vthreard.php and all its in its place, i dont now what to do, i didnt touch any of the avatars add on codes.. i wonder if theres a kind of incompatibility?
and other thing, when a user selects an avatar form the existing gallery, nothing happens... i just get a white screen. if i get back (using the browser buttons) to the preferences, i can see the "new" avatar.. but, i think i should display something when u select it, right?
well, i have been really trying to make the avatar work, with no success..