IIRC, you cannot access some things in your profile until you've posted 10 times or something like that. If you do not wish to post 10 times and want to remove your account, you might try the "Contact Us" link at the top (although I don't know how much they monitor all requests there). Otherwise, I'd say join in some productive conversations.
So funny I had the same issue and did contact them, funny thing is I used to be an admin for a forum site much like this one. It had been a while since I was newbie. LOL
I have to say, I don't like the idea of not being able to edit things like signature etc till I've reached 10 posts. Hopefully this is something that will be changed to match the rest of the group, i.e. SPE, CrackBerry, etc, etc...