what is wrong with my GUI script?

Hello, I am trying to display the score for my game on the GUI, but when I use my script the score will not show up, what is wrong with my script?

static var Score = 0;

function OnGUI()
 {
   GUI.Label(Rect(100,100, 100, 50), Score);
 }

function OnTriggerEnter (other : Collider) {
    if (other.gameObject.CompareTag ("Wall")) {
        Destroy (gameObject);};
    if (other.gameObject.CompareTag ("Enemy")) {
        Destroy (gameObject);
        Destroy (other.gameObject);
        Score += 100;}
   ;}

Add .ToString to Score so that Score is converted into a string, allowing it to be written to the label.

 static var Score = 0;

    function OnGUI()
     {
     GUI.Label (Rect (10, 10, 100, 20), Score.ToString());
     }

    function OnTriggerEnter (other : Collider) 
    {
        if (other.gameObject.CompareTag ("Wall")) 
    {
            Destroy (gameObject);
    }
        if (other.gameObject.CompareTag ("Enemy")) 
    {
            Destroy (gameObject);
            Destroy (other.gameObject);
            Score += 100;
    }
    }