Reference Error: Re Player not defined

[tjvg91]

Why do I get this error? This is my code:

if (!MIDI.Player.playing) {
MIDI.Player.loadFile("midi/All%20To%20Jesus%20I%20Surrender.mid", MIDI.Player.start(null), null, function (e1) { alert(e1); });
} else MIDI.Player.pause();

help please?