From the the SFC page - http://wordpress.org/support/topic/plugin-simple-facebook-connect-facebook-authorization-is-under-scott-wyden-imagery
NGG's ngg_social_media.js contains information that interferes with SFC.
eg: the line - js.src = "//connect.facebook.net/en_US/all.js#xfbml=1&appId=66864567775";
This is the Page/App Id of Scott Wyden Imagery - who says he is not associated with NGG
Looking for solution..