Comment 25 for bug 301189

It can't update itself because, if Vuze is installed by the Ubuntu package manager, it is installed system-wide and as a regular user, you do not have permission to modify the executable. If Vuze tries to update itself, it will not have permission, and fail. You may be able to force it somehow, but that's not a good idea, because then the version of Vuze that you have installed will be out of sync with the version that the Ubuntu package manager thinks you have.

Choices are:
 - Download Vuze from their web site, drop it somewhere in your home directory, and run it from there. It should be able to update itself fine.
 - Disable Vuze's automatic updates and rely on Ubuntu's update manager. Updates will be fewer and far between, but you get a nice pre-packaged app that gets installed for all users.

To solve this bug, I think that Vuze's built-in updater should be disabled (if you are using the version installed via Ubuntu's package manager), like it is with Firefox and some other apps. (However, Vuze should still be able to automatically check for updates to plug-ins that you have installed, because that works fine.)