Marketpress manual payments not working on one site of network

So we have Marketpress running perfectly for our entire network but I was just made aware of something odd on one of our subsites.

All the other subsites have both Manual Payments and Paypal as payment options but this one has manual payments only.

When you go through the checkout process the confirmation page just keeps reloading and the order can't be completed.

The site is and the site having the issue is

If you go to Class Dates you can add products to cart from there and go through the process.

I'm stumped because it works just fine on every other site but this one is the only one having issues.

Any help you can give me is much appreciated!