What extensions including the version numbers are installed?
The extensions that are compatible with Dreamweaver CS^ and the latest versions are:
eCart 5.0.7
Free Tools 1.0.5
Design Extender 1.1.5
Data Bridge 1.1.4
I recommend installing them in the order listed above.
If you have an older version of one of the extensions installed, you should uninstall it before installing the newer one.