Please attach a copy of the shopping cart file you are using and the page where you are using it. I'll take a look and see if I can spot the issue.
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.