Website now says this:

Oops, looks like there was a problem with your registration!We're experiencing some technical difficulties at the moment, but are in the process of fixing it. Check back in a few days and you should be able to register then. After you register, all you need to do is stay just once by December 31 and you'll earn an easy 4,000 Bonus Points. Only members who received a dedicated email about this offer are eligible.