Sounds like the configuration folder has become corrupted.
recreate the users configuration folder as outlined in step 12 of the Adobe troubleshooting guide:
http://helpx.adobe.com/dreamweaver/kb/troubleshoot-javascript-errors-dreamweaver-cs4.html#main_user_config
After renaming the configuration folder, open DW to recreate it, close DW and open the extension manager.
In the extension manager, uninstall the extensions and reinstall them. make sure to download the latest versions from the download center.