Gustavo,
Everything's going great here! We're actually at the Joomla World Conference chatting about Facebook, meeting great developers, and having a great time. Thanks for asking!
I just tested on your site and the comment refreshed properly without having to reload the page. I was testing with Chrome on a Mac, just so you know.
As for possible reasons for the problem, if you're still having it.. I'm not honestly sure. Our JFBCComments module actually generates a {JFBCComments} tag that is then later replaced, so the underlying functionality is actually the same. A couple things to try would be:
* Try disabling the AddThis module/plugin
* Disable your optimization plugins/extensions that your using.
Try after each and see if it helps. If so, we'll help you re-enable that functionality.. we just need to narrow things down first.
Thanks,
Alex