What version of Data Bridge do you have installed?
The curent version is 1.2.1, if you have a previous version installed, make sure to uninstall it from the extension manager before installing the new one.
After installing the extensions, open Dreamweaver, this should start the WebAssist installer. If the WebAssist installer does not start, you may need to open a PHP page to force it to launch.
after the WebAssist installer completes, make sure to restart Dreamweaver.