AudioSource problem Unity4.0, need help

I have a big problem , this always worked with my previous version of unity but with unity 4.0 i get an error saying " cannot play a disabled audio source" , whenever my ship is hit by the lazer there should be a explosion and a sound effect but now there is no sound effect .

var explosionPrefab : Transform;

public var PlayerShip : GameObject;

var hitexplosion1 : AudioSource;

function OnCollisionEnter(collision : Collision) {

if(collision.gameObject.tag == "lazerhit2"){ 

   print ("you have been hit");
   var player  = Instantiate (explosionPrefab, GameObject.Find("afship").transform.position,Quaternion.identity);
  // Destroy (gameObject,GameObject.Find("bluelazer(Clone)");
  hitexplosion1.Play();
    shipHealth.lives -= 1;
  Destroy (gameObject);
   } 
   
   
   }

public var PlayerShip : GameObject;
var hitexplosion1 : AudioClip;
var shipPos:Transform;

function Start(){
    shipPos = GameObject.Find("afship").transform;
}

function OnCollisionEnter(collision : Collision) {
    if(collision.gameObject.tag == "lazerhit2"){ 
    var player  = Instantiate (explosionPrefab, shipPos.position,Quaternion.identity);
    AudioSource.PlayClipAtPoint(hitexplosion1, shipPos.position); 
    shipHealth.lives -= 1;
    Destroy (gameObject);
}

That should do it. AudioSource creates an audio source object that gets automatically destroyed once the sound is done.