line renderer problem

i have created a line renderer and attached to the cube when mouse moves around the screen the line renderer should move around the mouse i have attached the scripts to the cube while i am trying to move mouse it line renderer is not moving i have attached my sample code

var cube1 : Transform; var m_pos : Vector3; //mouse postion var line : LineRenderer ; //line renderer

  function Update()
  {
  var lineRenderer : LineRenderer = GetComponent(LineRenderer);
  var ray = camera.main.ScreenPointToRay(Input.mousePosition);
  var pos : Vector3 = ray.GetPoint(10);
  m_pos = pos;
  Debug.Log(m_pos);

  if(Physics.Raycast(ray))
  {
  first();    //function
  }
  }


  function first()
  {
  line.SetVertexCount(2);  
  var pos1 : Vector3 = cube1.transform.position;
  var pos2 : Vector3 = m_pos;
  line.SetPosition(0,pos1);
  line.SetPosition(1,pos2);
  }

line render is not moving around the mouse it is staying in fixed postion without any change i have coyped cube transform postion into line renderer postion then also it is not working