Checkout Not working in Coursepress/MarketPress

Since the new update, my checkout isn't working.

You can try purchasing this product: http://www.thepodcasthost.com/university/courses/podcast-liberation-set-your-podcast-free/

And you'll see that when you click 'signup' on the course then you'll signup, but then be told that you have nothing in your cart.

Please help with this - customers currently aren't buying my products because of this issue!