Calling a Function in a Component

Question

Hi I know this is simple but I can not get this to work I ahve looked for example but come uo with nothing
I want to call a function in a  Component
I created  acompoinent based on a label
<?xml version="1.0" encoding="utf-8"?><mx:Label 
xmlns:mx="http://www.adobe.com/2006/mxml"> 
   <mx:Script>
     <![CDATA[
       public var mp3:String; 
     private var soundChannel:SoundChannel; 
// this function will load and play the sound 
    public function playSound():void{ 
       var urlRequest:URLRequest = new URLRequest(mp3);  
      var sound:Sound = new Sound();     sound.load(urlRequest);
// will stop sound of no device is found  
     if(soundChannel != null ) {         soundChannel.stop();
     soundChannel = sound.play();
// this function stops the sound from playing, this need tos work on the sound channel  
    private function stopSound():void
     {        soundChannel.stop();
     ]]>
  </mx:Script>
</mx:Label>
calling looks like  
<?xml version="1.0" encoding="utf-8"?><mx:Application 
xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" xmlns:uofs="uofs.*" > 
<uofs:ulable text="hellow" id="b21" x="200" y="300" mp3="jazz.mp3" click="playSound()" /> 
 </mx:Application>
also how wolud you pass a string in the click
click="playSound(jazz.mp3)"  or click="playSound("jazz.mp3")"
do not work  

Answer 1

ok, thanks i got it
becouse is called the instance of the component id="b21"  the the click ="b21.playsound()"
ie use the function playSound in the instance of the compinent b21
still does not work
Error #2044: Unhandled IOErrorEvent:. text=Error #2032: Stream Error.
at uofs::ulable/playSound()[C:\Documents and Settings\Administrator\My Documents\Flex Builder 3\CompinentTest\src\uofs\ulable.mxml:17]
at CompinentTest/__b21_click()[C:\Documents and Settings\Administrator\My Documents\Flex Builder 3\CompinentTest\src\CompinentTest.mxml:4]
but that is something diffrent that I will look at next
thanks for the help