I do have the problem, that Friends only ignores your whitelisted URLs inside the sentry.php . In example the plugin ask for authentication on /wp-admin/ and the /xmlrpc.php.
My Installation is an WordPress 3.4.1 and the Friends Only Plugin 0.6.0. The PHP installation is an 5.3.10. My wordpress installation is not inside the root directory of my website but under a subdirectory called glog.
Could you please give me advice on how to get Friends only running?