Update Twitter Tools today to my WordPress Multisite / Network install running 3.4.2. Installed the necessary Social plugin. Users page returning 500 error constantly when installed and working fine when deactivated - clearly something interfering with Users. Also, 500 error also returned when clicking the "Tweets" area from admin panel. Site also slows right down. Clearly some issues with this update and integration with Social - particularly and specifically true of two unique and separate multisite installs.