Make sure that you have the server behaviors extension installed:
http://www.webassist.com/tutorials/Server-behaviors-for-Dreamweaver-Creative-Cloud
also, make sure you have the latest versions of the web assist extensions installed:
eCart 6.0.3
Design Extender 1.1.7
Data Bridge 1.1.8
if you have previous versions installed, you should uninstall them before installing the newer ones.
after the install competes, open DW and open a PHP to start the WebAssist installer.
after the WA Installer completes, don't forget to restart DW.