Pro Sites Setup

How do I get Pro sites working on my blog?

If a new user signs up though wp-signup.php?Pro+Site=1 they are asked for a username and email address and after confirming they can log into the blog. There is no "checkout" process, they are not asked to sign up for a Pro account, they just get membership to the blog.

Being a member does not give them any privileges, and they would be unable to upgrade even if they wanted to. They cannot access wp-admin, or do anything at all on the front end except maybe leave a comment.

I have set up accounts in admin, with sites, these sites are able to login to wp-admin add sites and upgrade etc, but unless I create the account myself, this does not happen. I have been though all the pro sites settings and everything seems ok. PayPal is working (for the accounts that I can upgrade).

How do I get this working?