Hi
look here:
http://www.subsim.com/radioroom/showthread.php?t=228717 similar problem.
BTW I also tried to register to that forum today and no luck as well.
Will try again and if ever successful will let know.
EDIT: it works but only if you use that signup through sponsor. Hit that blue button "itTopicit" next to login and will log you through gmail or facebook etc.