I have just tried to setup facebook from our site.
It all goes well until I activate, the last lines of the log are:
-= Using API =-
Fatal error: session_start(): Failed to initialize storage module: memcache (path: /tmp/) in /var/sites/t/*********/public_html/wp-content/plugins/social-networks-auto-poster-facebook-twitter-g/inc-cl/apis/facebook.php on line 1502