Rated 3 out of 5 stars

yazan: bode tarih: Nisan 3, 2011 ·

Since upgrading to FF4, I have been unable to use Fire FTP. It disconnects whenever I try to access the htdocs folder.
Very disappointing because I used it all the time previously, and now have to use an external FTP client.

This review is for a previous version of the add-on (1.99.2.1-signed). 

yazan: Mime Čuvalo (Geliştirici) tarih: Nisan 3, 2011 ·

Try the latest version, 1.99.3 it might solve your issue:
https://addons.mozilla.org/en-US/firefox/addon/fireftp/versions/