Hello,
I am using this plugin on a WordPress MultiSite install, and I have it set to allow each sites plugins to be activated from their admin panel. I have activated this plugin from there, and it gives me the message of "plugin activated" but there is no option to get into the settings. It does not show up anywhere in the side bar options in the admin panel screen.
http://wordpress.org/extend/plugins/social-networks-auto-poster-facebook-twitter-g/