after installing Data Bridge in the Extension manager, did the WebAssist installer run when you opened DW?
try uninstalling Data Bridge, then installing it again. when you open Dreamweaver the WebAssist installer should run to finish the installation, if not open a php page to trigger the installer. After the webassist installer completes, make sure to restart DW.
TO add universal email to a page, go to:
WebAssist -> Create Email Message.