cant assign variables value

i have a ai script but i cannot assign the target variable. i dont know whats wrong could someone tell me please? here is the code

 var IsPlayingOtherAnim = false;
 var Distance;
 var Player : GameObject;
 var lookAtDistance = 25.0;
 var ChaseRange = 15.0;
 var attackRange = 1.5;
 var moveSpeed = 5.0;
 var Damping = 6.0;
 var AttackRepeatTime = 1;
 static var TheDamage = 10;
 
 private var attackTime : float;
  
 var controller : CharacterController;
 var Gravity : float = 20;
 private var MoveDirection : Vector3 = Vector3.zero;
 
 
 
 
 function start () 
 {
     attackTime = Time.time;
     Player = GameObject.Find("Player");
     
 }
 
 function Update ()
 {
        
   
 
     Distance = Vector3.Distance(Player.position, transform.position);
     
     if (Distance < lookAtDistance)
     {
         lookAt();
     }
     
     if (Distance > lookAtDistance)
     {
         renderer.material.color = Color.green;
     }
     
     if (Distance < attackRange) 
     {
         Attack();
     }
     
     else if (Distance < ChaseRange)
     {
         Chase ();
     }
 }
 
 function lookAt ()
 {
     
     
     renderer.material.color = Color.yellow;
     var rotation = Quaternion.LookRotation(Player.position - transform.position);
     transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * Damping);
 }
 
 function Chase ()
 {
     
     
     renderer.material.color = Color.red;
     
     moveDirection = transform.forward;
     moveDirection *= moveSpeed;
     
     moveDirection.y -= Gravity * Time.deltaTime;
     controller.Move(moveDirection * Time.deltaTime);
     
 }
 
 function Attack ()
 
 {
     if (Time.time > attackTime) 
     {
     
     Player.SendMessage("ApplyDammage", TheDamage, SendMessageOptions.DontRequireReceiver);
     Debug.Log ("the enemy has attacked");
     attackTime = Time.time + AttackRepeatTime;
     
     }    
 }
 
 function ApplyDamage ()
 {
     ChaseRange = 30;
     moveSpeed = 4;
     lookAtDistance = 40;
 }