I'd need FTP access to debug it. It has to be something wrong with the code on the confirm_cart.php page, but without direct access to that page I couldn't determine what exactly.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.