Ivan,
I really just got to look through your page's code and noticed a few things that may, or may not, be related:
1) You're using the Share button from Facebook. This button has been deprecated by Facebook, and specifically, the sharer.php file that you're loading has been known to cause Javascript conflicts with Facebook's own library. It's possible this is part of the problem. If you can disable it, even temporarily to test, that would be great. The
Like button has all the features of the Share button and is recommended by Facebook to replace the Share button.
2) The social block of 4 things on the left may be problematic, but I don't see any reason why. Again, if you can disable it to test and see what happens, that'd be great to know how it goes.
Finally, as for re-ordering the code, you may want to try the non-asynchronous code from Facebook. It's similar to what we have, and I'm sure you can implement it instead of what we have in the jfbcsystem.php file. For information, check out Facebook's docs below which should make it pretty clear:
developers.facebook.com/docs/reference/javascript/FB.init/
If any of the above helps, or doesn't work at all, definitely let us know. Hopefully, we can get to something that works even if it means something is disabled, and then move on from there. I don't see any reason that mootools isn't loading properly, which the Javascript error from the JTabs script is saying is the problem. JFBConnect doesn't use Mootools, so it's not something we're specifically doing.
We'll get you going though.
Alex