I believe that most folders ending in <code>.files</code> are usually for storing cookies or other website specific data. If you trace the file path for that folder, it usually is located inside of a folder called <code>http+++[Website Address].com</code>, which denotes which website that data is related to. Nevertheless, you shouldn't have any issues with your backup profile if you choose not to backup those files. If you do want to attempt to move those files, ensure that Firefox is completely closed and that you are logged into an administrator account.