Doh! Ok, try "dcop kicker kicker restart" on a command line. Sorry I forgot about needing KMenu which is in the Panel to get to Control Center (I've got buttons mapped to bring up KMenu as well as docking it in the Panel). If you can't get to xterm in KDE because it's also hiden, you should be able to do this in Maemo xterm as well.

After you've got it back I would suggest using Control Center (as above) to change your settings. I've done a quick Google search and this disappearing Kicker (aka Panel) appears to be a bug in KDE.