tonypisa, Can't find any problems with the info you have given and the sample seems quite standard. It may be an idea to give your player a Fat format if you can just to rule out any bad sector or memory problems.
Also extracting, repairing and reloading the firmware can sometimes help, but if you can play the sample no probs i doubt this would make any difference.
I have done another sample for you but this time I have pre-processed the video and resized, reset the frame rate etc prior to converting it to AMV.
http://uploaded.to/?id=a9afae