What firewall setting on my VPS?

No incoming connections really need to be opened, but the following are sites that JFBConnect can try to communicate with:
api.facebook.com/
api-video.facebook.com/
api-read.facebook.com/
graph.facebook.com/
www.facebook.com/

If you're running into specific issues, just let us know,
Alex

Ahh... that checks our site actually for an XML file with the latest available versions for JFBConnect. The file is below:

www.sourcecoast.com/versions/jfbconnect.xml

Just so you know, we have no tracking or logging or any queries to that URL, it's purely for information and is openly accessible.

Hope that helps,
Alex