Hello gramax, I'm sorry to hear that you are experiencing issues with Fire FTP, but unfortunately don't think that there is anything to do on our side. You should probably ask for help on Ubuntu's side at either the [http://ubuntuforums.org/ Ubuntu forums] or askubuntu.com. The IRC (irc://irc.freenode.net#ubuntu) might also be a good idea. There is also the possibility to ask directly at Fire FTP (http://fireftp.mozdev.org/help.html). If nothing of this works, make sure that your Add-On is up-to-date. Thank you for your patience and valuable time and please mark this answer as solution if it was helpful. Surf safe and have a great day!