Add to cart and drop down menu aren't working for Marketpress

Hey,

I've got Marketpress installed on my main site and on my sub-domain. The store on my sub-domain is working perfectly fine. The store on my main site is having some issues. The ajax menu isn't work at all. Also, when I hit "add to cart" there's a spinning wheel, but no action. The product never gets moved to the shopping cart.

Any insight?