i'm having a problem with non-updating playcounts too. also with the movies stalling at the end.
what's interesting is that the playcounts update on the actual nano; if you go to itunes and look at the playcounts within the nano's movie section, they are updated from the nano's POV. for example, say video X got 3 plays before you put it on the nano. then you put it on the nano. while you use the nano, you play video X twice. when you connect it back to your PC, the playcount on the main itunes section will still be 3 but on the nano's movie section it will be 5. it will be 5 even if the video stalled at the end both times.
i also tried putting videos in a playlist and it still stalls.
videos on my old 5G pod video don't stall. however they no longer skip to the next video, but go back to the menu (maybe this started happening a long time ago but i never updated the firmware til recently).
oh well. i just hope the patch gets made.