Error: Download of swfupload_f9.swf returned response code 404

If you encountered a WordPress Error with returned response code of 404 you’ve come to the right place. This is the common error that was encountered after upgrading to WordPress 2.6 and activating Google Gears. Error: Download of {your domain}/wp-includes/js/swfupload/swfupload_f9.swf returned response code 404 is the exact error message inside your administration panel.