ddny,
EasyBlog - Social Integration. Under the "Facebook" tab, I set "Load Facebook Scripts" to No.
EasyDiscuss - Social Integration. Under the "Facebook" tab, I set "Load Facebook Scripts" to No.
sh404 - set JFBConnect set "Leave as non-sef"
There's still something else Facebook related on your site, but I can't find it. If you open the HTML of your page and search for "all.js", you'll see it's in there twice. That's the Facebook Javascript library and it should only be loaded on the page twice. Not sure what other extension is adding it, but the 2nd load should be removed. With it in there twice, some browsers may run into issues.
Either way, I just tested with Chrome on Windows and was able to register and login as expected. Obviously, please test. It's possible the issue is intermittent and still there, but hopefully, it's fixed.
Please let me know,
Alex