It worked at last Puntuado con 5 de 5 estrellas
When I first tried it, it was buggy and didn't work.
I opened Firefox error console and discovered that errors were caused by the Arabic characters in the geolocation data I enter (street, city name, etc.). I had to clear the "extensions.geolocater.localhost" configuration from Firefox configurations page (about:config), and re entered my geolocation data but all in ASCII characters, and it worked at last.
This plugin can't handle non ASCII characters I think