UnassignedReferenceException: The variable highScore3DText of 'Menuscene' has not been assigned

private var ray : Ray;
private var rayCastHit : RaycastHit;
var highScore3DText :TextMesh;

function Awake ()
{
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 7

The error is self-descriptive. You haven’t assigned a value to highScore3DText.