Marketpress checkout not going to confirmation page

Greetings!
This is for http://www.lucidallusion.tamanasprings.com/

I'm having customers have multiple orders go through because when the "Submit Order" button is pressed the order goes through after the loading wheel loads but the page doesn't change.

Screenshot 1 shows the page after the button is pressed and the loading wheel disappear.
Screenshot 2 shows the order goes through.

Why is this happening, and how can I make the process go to the order confirmation page?