I'm unsure what's happening on that page, but it looks like the JFBConnect system plugin is executing 2 times. The Facebook Javascript library is being loaded twice and that's likely what's causing the comments box to not load properly.
I can't see any reason why the JFBConnect system plugin is behaving that way on the page. What I would recommend doing is re-ordering your system plugins. Please try moving the JFBCSystem plugin to the first ordered position and test. If that doesn't work, try moving it to the last ordered position and test.
Hopefully, re-ordering will help fix the issue, but if not or you need further assistance, please let me know.
Thanks,
Alex