Help! the enemy incline when attacks player

I add to script to Model with animation

But the enemy incline

Look:

the IA enemy script requires audio source adn Fps Input controller

this is:

 var Distance;
 var Target : Transform;
 var lookAtDistance = 25.0;
 var chaseRange = 15.0;
 var attackRange = 1.5;
 var moveSpeed = 5.0;
 var Damping = 6.0;
 var attackRepeatTime = 1;
 var TheDammage = 40;
 private var attackTime : float;
 var controller : CharacterController;
 var gravity : float = 20.0;
 var Troll : AudioSource;
 var Zombie : GameObject; //The Model who contains the animations
 private var MoveDirection : Vector3 = Vector3.zero;
 
 function Start ()
 {
     attackTime = Time.time;
 }
 
 function Update ()
 {
     if(RespawnMenuV2.playerIsDead == false)
     {
         Distance = Vector3.Distance(Target.position, transform.position);
         
         if (Distance < lookAtDistance)
         {
             lookAt();
         }
         
         if (Distance > lookAtDistance)
         {
             
         }
         
         if (Distance < attackRange)
         {
             attack();
         }
         else if (Distance < chaseRange)
         {
             chase ();
         }
     }
 }
 
 function lookAt ()
 {
     var rotation = Quaternion.LookRotation(Target.position - transform.position);
     transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * Damping);
 }
 
 function chase ()
 {
     Troll.Play();
     Zombie.animation.Play("Walking", PlayMode.StopAll);
     moveDirection = transform.forward;
     moveDirection *= moveSpeed;
     
     moveDirection.y -= gravity * Time.deltaTime;
     controller.Move(moveDirection * Time.deltaTime);
 }
 
 function attack ()
 {
     Zombie.animation.Play("Attacking", PlayMode.StopAll);
     if (Time.time > attackTime)
     {        
         Target.SendMessage("ApplyDammage", TheDammage);
         Debug.Log("The Enemy Has Attacked");
         attackTime = Time.time + attackRepeatTime;
     }
 }
 
 function ApplyDammage ()
 {
     chaseRange += 30;
     moveSpeed += 2;
     lookAtDistance += 40;
 }
  

Help me please :(