Wait, it's a little easier than you think. You appear to be installing LinuxMCE 1.0 on Ubuntu, that is correct but that is not the latest edition. Linux MCE 1.1 Beta is the latest version and runs on top of KDE, and so kubuntu is required. If you install Kubuntu, you'll need to use the Beta which (AFAIK) is currently only available via Bittorrent.
HTH
-Chad