How to randomize songs in a Flash Jukebox - conntected to an XML databse

I putted it into my code and that made me this :

var my_songs:XMLList;

var my_total:Number;

var my_sound:Sound;

var my_channel:SoundChannel;

var current_song:Number = 0;

var song_position:Number;

var song_paused:Boolean;

var myXMLLoader:URLLoader = new URLLoader(); // naakt een nieuwe XML loader

myXMLLoader.load(new URLRequest("playlist.xml")); // load playlist.xml

myXMLLoader.addEventListener(Event.COMPLETE, processXML); // event aan maken

var singNums:Array = new Array();

function processXML (e:Event):void // roept funcite aan

{

          var myXML:XML = new XML(e.target.data);

          my_songs = myXML.SONG;

          my_total = my_songs.length();

     for(var i:uint=0; i<my_total; i++){

               songNums.push(i);  // this just builds an array of numbers [0,1,2,3,4,....]

     }

    shuffle(songNums);  // randomizes the numbers in the array

    playSong(songNums[current_song] );

}

function shuffle(a:Array) {

    var p:int;

    var t:*;

    var ivar:int;

    for (ivar = a.length-1; ivar>=0; ivar--) {

        p=Math.floor((ivar+1)*Math.random());

        t = a[ivar];

        a[ivar] = a

;

        a

= t;

    }

}

function playSong(mySong:Number):void

{

var myTitle = my_songs[mySong].@TITLE;

var myArtist = my_songs[mySong].@ARTIST;

var myURL = my_songs[mySong].@URL;

          title_txt.text = myTitle;

          artist_txt.text = myArtist;

          if (my_channel)

          {

                    my_channel.stop();

          }

          my_sound = new Sound();

          my_sound.load(new URLRequest(myURL));

          my_channel = my_sound.play();

          my_channel.addEventListener(Event.SOUND_COMPLETE, onNext);

}

next_btn.addEventListener(MouseEvent.CLICK, onNext);

function onNext(e:Event):void

{

          current_song++;

          if (current_song>=my_total)

          {

                    current_song=0;

          }

          playSong(current_song);

}

prev_btn.addEventListener(MouseEvent.CLICK, onPrev);

function onPrev(e:MouseEvent):void

{

          current_song--;

          if (current_song<0)

          {

                    current_song = my_total-1;

          }

          playSong(current_song);

}

pause_btn.addEventListener(MouseEvent.CLICK, onPause);

function onPause(e:MouseEvent):void

{

          if (my_channel)

          {

                    song_position = my_channel.position;

                    my_channel.stop();

                    song_paused=true;

          }

}

play_btn.addEventListener(MouseEvent.CLICK, onPlay);

function onPlay(e:MouseEvent):void

{

          if (song_paused)

          {

                    my_channel = my_sound.play(song_position);

                    song_paused=false;

          }

}

I am getting 3 errrors :

Scene 1, layer 'action', frame 1, sentence 28   1120: Using undefined songNums

Scene 1, layer 'action', frame 1, sentence 31   1120: Using undefined songNums

Scene 1, layer 'action', frame 1, sentence 33   1120: Using undefined songNums

How can I fix this?

Many thanks in advance!