I too have been experiencing this problem. I'm running tvengine3 and RC1 with SVN 15417 in a single seat setup on an XP machine. Miniguide is working and I can even search shows from the tv preview screen. But when I goto the guide it just says "label missing" and ther's no channel logos either. Tried hittin F9 but nothing happened.
Make sure you have installed the corresponding MP SVN update.
England