Instead of clicking on the link, copy it and paste it into your browser. That's how I got in.
http://www.psych.upenn.edu/~baron/qs.html
I only got on his waiting list, but at the bottom of that page is a list of additional survey sites you can sign up for, at least half of them were new to me. Hope this helps!
PS: I just clicked on the link I put in this message and it works fine. Go figure! ROTFL