Updating Xubuntu Feisty to Gutsy using Nomachine NX

Be sure you have the latest 32bit or 64bit Nomachine NX client, node & server on your (mythtv-)server. And the latest nxclient on your desktop. Run nxclient and configure a connection to your (mythtv-)server. Change this connection to open an X11 console:

Configure > Desktop > Unix + Custom > Settings > Run the console

[OK] all dialogs and save the new config. Enter your credentials. In the console that opens after a while enter `gksu "update-manager -c"`. Update your distro. Then a new button will appear to upgrade to Gutsy. Follow the onscreen instructions.