Unable to play audio file in Internet Explorer 8 and 9

I get "SCRIPT16385: Not implemented" on jquery.media.file.js?r, line 32 character 7 when trying to play an audio file. That error is thrown on the first return statement of this script.

  // Checks the file type for browser compatibilty.
  jQuery.media.checkPlayType = function( elem, playType ) {
    if( (typeof elem.canPlayType) == 'function' ) {
      return ("no" !== elem.canPlayType(playType)) && ("" !== elem.canPlayType(playType));
    }
    else {
      return false;
    }
  };

I'm using PHP to display the player on a clean Drupal 6.26 install with MediaFront 6.x-1.5.

$audio_node = node_load(1);
$element = array('#formatter' => 'audio_', '#node' => $audio_node);
$player = theme('mediafront_formatter_audio_player', $element);
print $player;

It works perfectly in Chrome and Firefox. I've attached a screenshot of the debugging console.