One of the best firefox addons you will ever find Puntuado con 5 de 5 estrellas

The simplest and most intuitive FTP tool ever.I have been using this tools for a long time now and it is just great!! It has never failed on me!

Esta valoración es de una versión anterior del complemento (2.0.14). 

What's the issue you're having? Do you mean Firefox 21 compatible? (instead of 12)