About a enemy AI in my game

Hello, i made a rader simple AI script for one of the enemys in my game, now the problem is, he is losing his colliders when the game executes. i tried to put a Character controller, and there ar still no colliders. Here is the script -

var player : GameObject; 

var speed : float=6f; var range : float=10f; var hitRange : float=5f; var enemyDamage : float=10f; var rotationSpeed : float=5f; var damageTimer : float=0f;

@script RequireComponent (CharacterController)

function Update()

{ //move towards player var distance = Vector3.Distance(transform.position, player.transform.position); if(distance<=range) {
var delta = player.transform.position - transform.position; delta.Normalize(); delta.y = 0; var moveSpeed = speed Time.deltaTime; transform.position = transform.position + (delta moveSpeed);

transform.rotation = Quaternion.Slerp (transform.rotation, Quaternion.LookRotation(delta), rotationSpeed * Time.deltaTime); transform.eulerAngles = Vector3(0, transform.eulerAngles.y, 0);

 damageTimer+=Time.deltaTime;
 if (distance < hitRange && damageTimer>=1.5)
 {

     damageTimer=0f;
     player.SendMessageUpwards
         ("ApplyDamage", enemyDamage, SendMessageOptions.DontRequireReceiver);
 }

}

}

ill be glad if some 1 would be able to help me.