New registered members can not use the forum. every time they try to interact (either post, reply, or check the Private Message) they get a message saying "you're not registered blah blah".. But they are registered, although their username doesn't show up in the main page "Ultimate.cgi" nor the list in the CP, but I can see their files inside the Members directory.
This is my UBB,
http://www.demna.net/cgi-bin/Ultimate.cgi One last question, what does the "Rebuild Member Files" function do in the Misc. and Debugging link inside the CP? (will it help fix my problem?)