Alexander,
You look to have set a language override inside JFBConnect to "pt-BR". You need to use an underscore, not a dash, so it should be pt_BR. Once you do that, it should fix things up.
I just saw your PM with other details. The pages that the FB button does show up on has another Facebook extension installed on it that's also loading the Facebook Javascript library. That wil likely cause issues on those pages, and should be disabled (or configured to not load the JS library). Just wanted to point that out.
Fantastic! Glad to hear we got you going, and we love the easy issues!
After you've played with JFBConnect a bit, please consider leaving a rating and review for it or our support on the Joomla Extension Directory. It's certainly not required, but very appreciated: extensions.joomla.org/extensions/social-...ook-integration/7215