What version of Data Bridge do you have installed? make sure you have the latest version 1.1.8. If you have a previous version installed, make sure to uninstall it from the extension manager before installing the newer one.
What is your version of Dreamweaver?
What is you OS?
have you tried the following:
reset the workspace layout:
go to Window -> Work Space layout -> Reset '<your layout name>'
and Delete the Dreamweaver Cache file from the users configuration folder: