I have 4GB of memory, so I don't think that is the issue. Furthermore many files play. Currently it is only Sunshine and Journey to the edge of the Universe that do not play, and neither of these play without hardware acceleration, so I guess this is a different issue. Also the audio issue reported previously with the narration track, was also a red herring, caused by conversion. I noticed my post got botched, check out the whole thread here:
I should have read more carefully, how do you increase the amount of video memory used? Is this a bios setting or an mplayer setting?