JFBConnect is picky about the order that our Javascript files are loaded. Each social network can also load their own Javascript, and they can be much more picky than JFBConnect. If you're using JFBConnect, please have it skip doing any optimizations for JFBConnect and our /components/com_jfbconnect/includes/jfbconnect.js file.
That should get you going, but if not, just let us know.
Thanks,
Alex