We recently released a new version of the quiz, and looks like we had an IE7 bug which we'll fix right away. BTW - 55% of Sproost visitors have been FF, only 25% have been IE7/6.
using FF 3.0.5 here. I get stuck on the 2nd step of the quiz. The spinner spins forever. However the funny thing is it appears to work fine in IE 8.0.6