no, eCart 4 is not compatible with DW CC, you will need to update to eCart 6 in oder to use it in DW CC.
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.