The add to cart buttons look to be set up OK, can you send a copy of the WA_eCart/eCart1_PHP.php file so i can see hiw the cart object is configured.
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.