I manage a lot of customer WP sites. I came up with a quick way to back out of this mess enabling access to the WP admin screen and put the plugin in a holding pattern. Use at your own risk.
- Delete better-wp-security plugin directory.
- Download 3.6.6 http://downloads.wordpress.org/plugin/better-wp-security.3.6.6.zip
- Upload better-wp-security folder into plugin directory.
- Edit better-wp-security.php to change the version number to 5.0 or some number high enough to stop any accidental "update". YOu can change this back to 3.6.6 when you decide to update.
- Run through all features and setup your security like you had it before.
- Check everything out. If everything is working right MAKE A NEW BACKUP RIGHT NOW