NullReferenceException: Object reference not set to an instance of an object

//This is comment
private var ray : Ray;
private var rayCastHit : RaycastHit;

var highScore3DText :TextMesh;

function Awake()
{
var highScore3DText :TextMesh;
highScore3DText.text = “High Score:” + PlayerPrefs.GetInt(“highScore”).ToString();
}

function Update ()
{

if(Input.GetMouseButtonDown(0))

{
ray = Camera.main.ScreenPointToRay(Input.mousePosition);
if(Physics.Raycast (ray, rayCastHit))
{
if (rayCastHit.transform.name == “PlayButton”)
{
Application.LoadLevel(“MainGame”);
}
}
}
}

error at line highScore3DText.text = “High Score:” + PlayerPrefs.GetInt(“highScore”).ToString()

var highScore3DText :TextMesh;

should be

var highScore3DText : TextMesh;
highScore3DText = GetComponent ( TextMesh ) ;