I'm see a theme...Maybe it's an XP thing? does it happen if you use another app? ie whatever came with the hvr2200? if not then it's probably a bug that needs to be worked out in TVServer can anyone provide a mini dump?
I haven't installed Powercinema (which is what came with my HVR2200) so I dunno.
Also, changing channels from Digital to Analog takes a looong time, but I don't think this is a mediaportal thing...