I know this will sound strange !
It has been a long time since I checked the forums page. Now when i've been there I noticed that I'm logged in Nuke but Logged out BB. I don't see my name as registered or else , but a guest because i'm logged off !

.. I have checked the
'Actual User Status' in the control panel and I found it
'Offline' !!
the funny part that when I click on "Post New Topic" it takes me to 'My Account' Page
I used to have a backup of my bbtonuke files so I have replaced them all -excluding the admin folder - with the old ones but I still have the same problem.
you can view the site at fo2club.com/center to see what I mean
//UPDATE
It's getting worst ! now I can't log in even as a registered user :S , when i enter the username and password is redirects me to a page says:
'Access Denied' !!!!!! Please help ..
note: I can only sign in as an Admin