I am unable to implement the Membership plugin - keep getting "You do not have sufficient...&q

When I activate your plugin, no admin menu is created. I try to enable the plugin using the top right menu function in red and I get an error message "You do not have sufficient permissions to access this page." I have deleted the plugin, redownloaded it, and tried re-installing it several times. I have also tried disabling all other plugins and am still getting the same errors. If this is not resolved this weekend, I will be requesting a refund and purchasing an alternative options. My site can be seen at bit.ly/1xbDCGy