Not sure what happened, but that site had no users for some reason. I’ve added your THATCamp account mfaragher as an admin to the site. Note that it’s affiliated with your gmail address, not your Wright address.
Do be sure not to test the registration form with the same account as you use to administer the site; sometimes that affects your ability to access it, although this looks like a different thing. Anyway, let us know if you have any more trouble!