registered only plugin logs me out of site

I am trying to setup a registered user only site. I have been trying to use the plugin registered only. With the plugin deactivated everything works fine. With it activated when I try to access posts and categories pages the site logs me out. I have tried versions 2.9 and 3.7.1 and exactly the same thing happens on both. I have tried different browsers. Have reinstalled both Word Press and the plugin. I can’t find a definitive answer anywhere that I have looked. Any help would be very appreciated