This has happened to me twice for no reason I can discern. Creating a new Firefox profile has not fixed my problem but a complete uninstall of Firefox has. By a complete uninstall I mean removing the Application Data folder (normally C:\Documents and Settings\User_Name\Application Data\Mozilla). You might want to just move this folder so you have a backup...in any case the bookmarkbackups folder will be used to restore your bookmarks to the new profile so don't trash it. After uninstalling Firefox and removing the Application Data folder a reinstall will get SpywareBlaster working again. But you will have to reinstall your extentions as well as your bookmarks (go to Bookmarks>Organize Bookmarks>Import and Backup>Restore>Choose File and find the .json file you saved in the above mentioned bookmarkbackups folder). If anyone has found an easier solution, please post. This one took me 30 minutes.