The download page needs a small tweak, it should go ahead and check if you have Silverlight 2.0 installed... and let you know that it won't work in that case. Or at least check that during the install. I went through the full install, restarted IE and ended up with this:

I understand that it can be hard to get it to work with a beta, but checking to see if the system requirements are met before doing an install would be very helpful.