Uninstalling and re-installing likely won't do anything, but it shouldn't really hurt either if you want to try. Just to make sure I understand the issue.. Like's are showing, but the comment box is not?
The post you mentioned is an EasyBlog post. Are you enabling EasyBlog's Facebook comments integration or are you trying to use JFBConnect's? There's definitely a lot of extensions interacting on that page, but we'll gladly help investigate and figure things out however we can.
Thanks,
Alex