trouble with smooth damping

script reference does not give good example for smooth damping. and what I came up with is this. In the game, I'm trying to get the Player's model to smoothly follow a point in the scene which is controlled by the player.

 var target : GameObject;
 var smoothTime = 0.3;
 private var Velocity = 0.0;
 
 
 function Update () {
     var x : float = Mathf.SmoothDamp(transform.position.x, target.position.x,
                                  Velocity, smoothTime);
     var y : float = Mathf.SmoothDamp(target.position.y, target.position.y,
                                  Velocity, smoothTime);
     var z : float = Mathf.SmoothDamp(target.position.z, target.position.z,
                                  Velocity, smoothTime);
        
     transform.position = Vector3(x, y, z);
 }

I'm not exactly sure how the mathf.smoothdamp function works and I get a null reference exception whenever I try to play this. Its probably something simple I've overlooked. Please and thanks for the help!