do you have a "strace" built for your device?
if so
ssh in. try running mplayer from ssh shell like the following:
First see what options it presents from the command line like err?
mplayer --help (or something, that usually does it.)
then try
mplayer mytune.mp3
(where it is a valid tune like /mnt/us/music/punk.mp3)
usually that gives you a large splurge of info on the command line while it does stuff (also
-v or
-vv are popular options - in many applications - to get extra info you can try them too, I don't run mplayer but the stuff I'm talking about is just generic "poke around and find stuff" stuff)
next step? look into the launch script for mplayer
(I'm assuming you have some sort of shortcut)
Then try running something similar from the command line
look again at slurge, if you are fortunate it will start "as usual" and then when you try to do your "Thing that makes it die" you will get some answers on the command line
last resort try switching the mplayer in the script to something like
(prefix stuff from script) /path/to/my/strace -o /mnt/us/logIcanread mplayer (other suffixed stuff from script)
then run it. make it die. read the log.
it's tough to do remote debugging "with just your mind" although Niluje, Knc1, Hawhill and Gm (and others) ALL appear capable of psychic debugging
The real reason for that is they spent time understanding the underlying structures of their respective apps/hardward/drivers (or whatever they are working on)
I hope that is decentish advice - if not - I hope someone will improve on it.
Really can't tell you why an app I don't run doesn't work on a device I don't own, BUT with a bit of digging maybe You can tell Us!
best of luck