It looks like Paypal didn't call back to the site. The new member I created shows as inactive. In paypal (developer area) I do see the purchase confirmation email that was generated for the transaction.
This is installed in multisite (which I certainly wouldn't suspect an issue!)
Is there an IPN activity log I can view in paypal?
What is the IPN url?
Hopefully there's a couple of known hoops to jump through out there