make sure you have installed the extensions in the proper order:
Design Extender 1.0.4
Data Bridge 1
If you install eCart after Design Extender or Data Bridge, it will cause similar errors
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.