Help with point and click movement

So i’m trying to do a point and click movement of a single unit in a RTS fashon and I have set up this script. i get this error, I’m new to scripting so any help would be great

NullReferenceException: Object reference not set to an instance of an object
Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.String cacheKeyName, System.Type cacheKeyTypes, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.Object args, System.String cacheKeyName, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
Boo.Lang.Runtime.RuntimeServices.Invoke (System.Object target, System.String name, System.Object args)
UnityScript.Lang.UnityRuntimeServices.Invoke (System.Object target, System.String name, System.Object args, System.Type scriptBaseType)
selct and move.Update () (at Assets/selct and move.js:12)

This is the script

var speed : float = 20.0;

var move : boolean;

var wantedPosition : Vector3;

function Update () {

if ( Input.GetMouseButtonDown ( 1 ) ) {

    var ray : Ray = Camera.Main.ScreenPointToRay ( Input.mousePosition );

    var hit : RaycastHit; 

    

    if ( Physics.Raycast (ray, hit) ) {

        move = true; 

        wantedPosition = hit.point + Vector3 ( 0.0, 30.0, 0.0 ); 

    }

}



if ( move ) {

    transform.LookAt ( wantedPosition );

    transform.Translate ( Vector3.forward *  Time.deltaTime * speed );

    

    if ( Vector3.Distance ( transform.position, wantedPosition ) < 0.10 ) {

        move = false;

    }

}

}

Have a look a this page

it explains what a NullReferenceException is.

Also try attaching MonoDevelop to Unity, it makes debugging applications a lot easier:

http://docs.unity3d.com/Documentation/Manual/HOWTO-MonoDevelop.html