I suggest you bug report it to Firefox.
https://bugzilla.mozilla.org/And maybe to Samsung, but probably little they can do about it.
I tried it on Firefox on the Nexus 7 and is worked fine. Android 4.3... My nexus is now 2 years old - That went fast! - Gulp.
I did get asked a question about activating plugins when i visited your page the first time. I said "yes".
I also see under settings that there is dev tools -> remote debugging... Probably debugging it via a computer with firefox - like with iOS Safari and safari on a mac.
Hmmm... Interesting. I found where to turn off the plugins and now it complains about requiring an updated browser or Flash plugin.
I can only assume that you will need to supply an OGG version in order for it to play through HTML5.
There are encoders at the end of this section:
http://jplayer.org/latest/developer-guide/#jPlayer-media-encodingI would have thought that Firefox was using the devices MP3 decoder, but obviously not.
$(this).jPlayer("setMedia", {
mp3: "childOfTheAngels-MJessen.mp3",
oga: "childOfTheAngels-MJessen.ogg"
});
supplied: "mp3,oga"
Let us know if that fixes it.