so I fill a USB key with an assortment of video files in all different formats and plug it in. all clips play in all major video players in windows, in the Z110 I get "unplayable video tracks will be skipped" after "unplayable video tracks will be skipped" as it runs through the entire thing not able to play a single file. I've eventually found a very small selection of videos which will play. they don't appear to be anything different than the others. how do I get these vids to play? please tell me it can be done with a freeware batch video converter.

Its a waste of time. Video over USB on these units doesn't work very well.

Have you checked what codecs and containers the files are using?