The instructions in Step 2 of the troubleshooting guide at
With Dreamweaver closed:
Delete (or rename to configuration_backup) the configuration folder . This will have the effect of disabling all of the installed extensions. You should open the Extension Manager and remove all extensions to clear the extension mangers cache. After removing the extensions you can then reinstall them making sure to download the latest versions.
It doesn't matter what you name (or delete it) it as long as DreamWeaver can't find it and is forced to recreate the folder. Get rid of the appropriate folder for your system and then use Extension manager to remove all of your extensions. This will give you a clean starting point.