try renaming the configuration folder as outlined in the step 12 of the adobve trroubleshooting guide:
http://helpx.adobe.com/dreamweaver/kb/troubleshoot-javascript-errors-dreamweaver-cs4.html#main_user_config
after that, restart the extension manager and uninstall Data Bridge and Design Extender. Uncheck the Depreciated Server Behavior then check it again to have it reinstall.
then open dreamweaver to create the initial menus.
close Dreamweaver, then reinstall design Extender and Data Bridge.
I have run into problems before where after installing the deprecated server behaviors, DW needed to opened and closed finish the install before installing other extensions.