External monitor issues?

I'm generally loving my TabletPC. It's just such a great tool to do one-to-one presentations on: you can just hold it in your hands while discussing, hand the whole machine over and let the other party see/experience what you want them to see and they can in turn show you what THEY mean...

This weekend however, for the second time in a row, I had problems using my TC 1100 tablet with a projector (one-to-many presentation...). It works for half a minute, and then the projector will seem to loose the signal. I had to continue my presentation on an external monitor instead of off a projecor... Bummer.

Today I investigated what this could be about by connecting an external monitor and seeing what frequencies the tablet is outputting. Something odd is definately going on, as with this particular monitor, each and every time I press the right mouse button (on the stylus, or on a usb mouse), the display will jump. It looks like it is loosing sync for a single scanline or so. I even found a projector that would display a blue screen for about half a second each time I pressed the right mousebutton.

Downloaded powerstrip to see if it is frequency dependent, but it doesn't seem to be. Next I'm updating my video drivers to some unofficial ones to see if that helps.