Synaptic has been dropped from Ubuntu 11.10, and is kind of replaced by the Ubuntu Software Center. GIMX tutorials tell to use Synaptic to add ‘universe’ to the software sources, that’s why they need to be updated. It’s possible to add ‘universe’ to the software sources with the Ubuntu Software Center, but it appears that there is a bug that prevents software sources to be refreshed in case a Live CD/USB is used. A work-around is to type “sudo apt-get update” in a terminal.
GIMX 0.25 installation in Ubuntu 11.10