Hello. 
My name is Aleksey Lekhtin. Email: byavl@papillon.ru
As it describe in mplayer doc I send to you debug report
and hope it will useful for yours.

1. One question is appeared when I coded other movie as DX50 -> MPEG2.
Converted was done successfully, but mplayer detect this movie as below:

Playing toyota1.avi.mpeg2.
Cache fill:  0,00% (0 bytes)    Detected AVI file format!
VIDEO:  [mpg2]  352x288  24bpp  25,000 fps  1123,4 kbps (137,1 kbyte/s)
VIDEO:  MPEG2  352x288  (aspect 1)  25,000 fps  1123,4 kbps (140,4 kbyte/s)
Information about clip:
 Software: MEncoder dev-CVS-041115-10:00-3.2.2
 
Two line with FOURCC! Is it right ?

Best regards...