Script Attack zombie

hello, I am sorry for my poor English.
I would like to create a IA which attacks my player.

I have to use script provided in a demonstration. (platform). my IA moves and attack the player, but all are just in “idle” (the animation of walk and attack does not engage) ... the script are after. can you help me please? thank you for your answer.

 /*
     animations played are:
     idle, threaten, turnjump, attackrun
 */
 
 var attackTurnTime = 0.7;
 var rotateSpeed = 120.0;
 var attackDistance = 17.0;
 var extraRunTime = 2.0;
 var damage = 1;
 
 var attackSpeed = 5.0;
 var attackRotateSpeed = 20.0;
 
 var idleTime = 1.6;
 
 var punchPosition = new Vector3 (0.4, 0, 0.7);
 var punchRadius = 1.1;
 
 // sounds
 var idleSound : AudioClip;    // played during "idle" state.
 var attackSound : AudioClip;    // played during the seek and attack modes.
 
 private var attackAngle = 10.0;
 private var isAttacking = false;
 private var lastPunchTime = 0.0;
 
 var target : Transform;
 
 // Cache a reference to the controller
 private var characterController : CharacterController;
 characterController = GetComponent(CharacterController);
 
 // Cache a link to LevelStatus state machine script:
 var levelStateMachine : LevelStatus;
 
 function Start ()
 {
     levelStateMachine = GameObject.Find("/Level").GetComponent(LevelStatus);
 
     if (!levelStateMachine)
     {
         Debug.Log("EnemyPoliceGuy: ERROR! NO LEVEL STATUS SCRIPT FOUND.");
     }
 
     if (!target)
         target = GameObject.FindWithTag("Player").transform;
     
     animation.wrapMode = WrapMode.Loop;
 
     // Setup animations
 animation.Play("idle");
     animation["threaten"].layer = 0;
     animation["turnjump"].layer = 1;
     animation["gothit"].layer = 1;
     animation["gothit"].layer = 1;
     
     // initialize audio clip. Make sure it's set to the "idle" sound.
     audio.clip = idleSound;
     
     yield WaitForSeconds(Random.value);
     
     // Just attack for now
     while (true)    
     {
         // Don't do anything when idle. And wait for player to be in range!
         // This is the perfect time for the player to attack us
         yield Idle();
 
         // Prepare, turn to player and attack him
         yield Attack();
     }
 }
 
 
 function Idle ()
 {
     // if idling sound isn't already set up, set it and start it playing.
     if (idleSound)
     {
         if (audio.clip != idleSound)
         {
             audio.Stop();
             audio.clip = idleSound;
             audio.loop = true;
             audio.Play();    // play the idle sound.
         }
     }
     
     // Don't do anything when idle
     // The perfect time for the player to attack us
     yield WaitForSeconds(idleTime);
 
     // And if the player is really far away.
     // We just idle around until he comes back
     // unless we're dying, in which case we just keep idling.
     while (true)
     {
         characterController.SimpleMove(Vector3.zero);
         yield WaitForSeconds(0.2);
         
         var offset = transform.position - target.position;
         
         // if player is in range again, stop lazyness
         // Good Hunting!        
         if (offset.magnitude < attackDistance)
             return;
     }
 } 
 
 function RotateTowardsPosition (targetPos : Vector3, rotateSpeed : float) : float
 {
     // Compute relative point and get the angle towards it
     var relative = transform.InverseTransformPoint(targetPos);
     var angle = Mathf.Atan2 (relative.x, relative.z) * Mathf.Rad2Deg;
     // Clamp it with the max rotation speed
     var maxRotation = rotateSpeed * Time.deltaTime;
     var clampedAngle = Mathf.Clamp(angle, -maxRotation, maxRotation);
     // Rotate
     transform.Rotate(0, clampedAngle, 0);
     // Return the current angle
     return angle;
 }
 
 function Attack ()
 {
     isAttacking = true;
     
     if (attackSound)
     {
         if (audio.clip != attackSound)
         {
             audio.Stop();    // stop the idling audio so we can switch out the audio clip.
             audio.clip = attackSound;
             audio.loop = true;    // change the clip, then play
             audio.Play();
         }
     }
     
     // Already queue up the attack run animation but set it's blend wieght to 0
     // it gets blended in later
     // it is looping so it will keep playing until we stop it.
     animation.Play("attackrun");
     
     // First we wait for a bit so the player can prepare while we turn around
     // As we near an angle of 0, we will begin to move
     var angle : float;
     angle = 180.0;
     var time : float;
     time = 0.0;
     var direction : Vector3;
     while (angle > 5 || time < attackTurnTime)
     {
         time += Time.deltaTime;
         angle = Mathf.Abs(RotateTowardsPosition(target.position, rotateSpeed));
         move = Mathf.Clamp01((90 - angle) / 90);
         
         // depending on the angle, start moving
         animation["attackrun"].weight = animation["attackrun"].speed = move;
         direction = transform.TransformDirection(Vector3.forward * attackSpeed * move);
         characterController.SimpleMove(direction);
         
         yield;
     }
     
     // Run towards player
     var timer = 0.0;
     var lostSight = false;
     while (timer < extraRunTime)
     {
         angle = RotateTowardsPosition(target.position, attackRotateSpeed);
             
         // The angle of our forward direction and the player position is larger than 50 degrees
         // That means he is out of sight
         if (Mathf.Abs(angle) > 40)
             lostSight = true;
             
         // If we lost sight then we keep running for some more time (extraRunTime). 
         // then stop attacking 
         if (lostSight)
             timer += Time.deltaTime;    
         
         // Just move forward at constant speed
         direction = transform.TransformDirection(Vector3.forward * attackSpeed);
         characterController.SimpleMove(direction);
 
         // Keep looking if we are hitting our target
         // If we are, knock them out of the way dealing damage
         var pos = transform.TransformPoint(punchPosition);
         if(Time.time > lastPunchTime + 0.3 && (pos - target.position).magnitude < punchRadius)
         {
             // deal damage
             target.SendMessage("ApplyDamage", damage);
             // knock the player back and to the side
             var slamDirection = transform.InverseTransformDirection(target.position - transform.position);
             slamDirection.y = 0;
             slamDirection.z = 1;
             if (slamDirection.x >= 0)
                 slamDirection.x = 1;
             else
                 slamDirection.x = -1;
             target.SendMessage("Slam", transform.TransformDirection(slamDirection));
             lastPunchTime = Time.time;
         }
 
         // We are not actually moving forward.
         // This probably means we ran into a wall or something. Stop attacking the player.
         if (characterController.velocity.magnitude < attackSpeed * 0.3)
             break;
         
         // yield for one frame
         yield;
     }
 
     isAttacking = false;
     
     // Now we can go back to playing the idle animation
     animation.CrossFade("idle");
 }
 
 function ApplyDamage ()
 {
     animation.CrossFade("gothit");
 }
 
 function OnDrawGizmosSelected ()
 {
     Gizmos.color = Color.yellow;
     Gizmos.DrawWireSphere (transform.TransformPoint(punchPosition), punchRadius);
     Gizmos.color = Color.red;
     Gizmos.DrawWireSphere (transform.position, attackDistance);
 }
 
 @script RequireComponent(AudioSource)