http://www.mplayerhq.hu/DOCS/HTML-single/en/MPlayer.html#vcd
Mplayer also does not play .wmv filesplays
This is the reason you are not able to copy the DAT file also.
I have experienced the same problem with mplayer.
I have no idea how to solve it but my experience is that gentoo linux
VCDs properly but OpenBSD doesn't.
However with DVDs, there is no such problem.
Best,
Girish