Marketpress Checkout Button not functioning

It would be greatly appreciated if someone could assist with a problem I am experiencing with Marketpress. My website is currently running Marketpress lite (I have purchased the premium but not yet installed it). When adding products to the shopping cart, everything works fine until the Shipping Information page where no matter what I try, the Continue Checkout button does not work. It is clickable (doesn’t appear to be a CSS issue) and clicking does make the cursor think and window seem to refresh. I have tried changing to the 2011 and 2010 default wordpress themes which resulted in no change (the button still does not work). I just added my Paypal API information (not sure if that would impact but it is a fairly new paypal account) and have manual payments enabled as well.

If someone could please help look into this it would be greatly appreciated. Thank you.