Each time i activate membership i have issues with my site

Could you help. Membership was working fine then i upgraded and now i either lose my site or i get a redirect loop as it i try to select pages. It would great until the last upgrade. I had my host revert to the last good time with the plugin but it still has issues. I need this plugin.

Thanks for you help. I have the plugin deactivated currently at http://www.elmd.org

Thanks again,

Tim