I'm developing a store and im having a major problem. when i click on the add to my cart button, instead of showing the cart with the item in it, it goes to a blank page. but if you hit the back button in the browser, it shows up in the cart in the sidebar of the site. if you go to the following link and add an item to the cart you will be able to see what i mean.

http://blockstaronline.com/shop/

Thanks in advance.

Mike