Moving script wont even move enemy no more?

I add the code in the //Start and the //End part else the rest is made by unity, i added this code to stop the enemy from laying on his face. code: var speed:float = 5; var directionChangeInterval:float = 1; var maxHeadingChange:float = 30; var target : Transform;

     var heading: float=0;
     var targetRotation: Vector3 ;
  
     function Awake (){
  
         // Set random initial rotation
         transform.eulerAngles = Vector3(0, Random.Range(0,360), 0);  // look in a random direction at start of frame.
  
         //StartCoroutine
         NewHeadingRoutine ();
     }
  
     function Update (){
 //Start
     var step = speed * Time.deltaTime;
  
 transform.position =Vector3.MoveTowards(transform.position, target.position, step);
 //End
         var controller : CharacterController = GetComponent(CharacterController);
  
         transform.eulerAngles = Vector3.Slerp(transform.eulerAngles, targetRotation, Time.deltaTime * directionChangeInterval);
         var forward = transform.TransformDirection(Vector3.forward);
         controller.SimpleMove(forward * speed);
 
         //Setting the position back to set rotation so it stands up
 
 
     }
  
     /// <summary>
     /// Repeatedly calculates a new direction to move towards.
     /// Use this instead of MonoBehaviour.InvokeRepeating so that the interval can be changed at runtime.
     /// </summary>
     while (true){
         NewHeadingRoutine();
         yield WaitForSeconds(directionChangeInterval);
     }
  
     /// <summary>
     /// Calculates a new direction to move towards.
     /// </summary>
     function NewHeadingRoutine (){
         var floor = Mathf.Clamp(heading - maxHeadingChange, 0, 360);
         var ceil  = Mathf.Clamp(heading + maxHeadingChange, 0, 360);
         heading = Random.Range(floor, ceil);
         targetRotation = new Vector3(0, heading, 0);
     }