have you installed all the window codecs
when u do "ls /usr/local/lib/codecs"
u should see a load of .dll files; unless you have your codecs installed somewhee else!?
this is the area where ir50_32.dll and vid_iv50.xa should live.
mplayer is telling you that these two files are not there.
do a
Code:
locate vid_iv50.xa and locate ir50_32.dll
and see if you can find them.