'GetSystemInterested(transform, system) != enable' UnityEngine.GameObject:SetActive(Boolean)

I am getting this error because I used for loop instead IEnumerator from the asset store. Which I learned from the forum. But I unable to use it because I am an absolute beginner. Somebody please rewrite the code. error at : 48, 64, 66, 55, 78, 88, 118

using UnityEngine; using System.Collections; using System.Collections.Generic;

public class HR_TrafficPooling : MonoBehaviour {

 #region SINGLETON PATTERN
 public static HR_TrafficPooling instance;
 public static HR_TrafficPooling Instance{
     get{
         if(instance == null)
             instance = GameObject.FindObjectOfType<HR_TrafficPooling>();
         return instance;
     }
 }
 #endregion

 internal Transform reference;
 public Transform[] lines;

 private bool animateNow{
     get{
         return HR_GamePlayHandler.Instance.gameStarted;
     }
 }

 public TrafficCars[] trafficCars;

 [System.Serializable]
 public class TrafficCars{
     public GameObject trafficCar;
     public int frequence = 1;
 }
 
 private List<HR_TrafficCar> _trafficCars = new List<HR_TrafficCar>();

 void Start () {

     reference = Camera.main.transform;
     CreateTraffic();

 }

 void Update(){

     if(animateNow)
         AnimateTraffic();

 }

 void CreateTraffic () {
     
     for (int i = 0; i < trafficCars.Length; i++) {

         for (int k = 0; k < trafficCars[i].frequence; k++) {
             GameObject go = (GameObject)GameObject.Instantiate(trafficCars[i].trafficCar, trafficCars[i].trafficCar.transform.position, trafficCars[i].trafficCar.transform.rotation);
             _trafficCars.Add(go.GetComponent<HR_TrafficCar>());
             go.SetActive(false);
         }

     }
     
 }

 void AnimateTraffic () {
     
     for (int i = 0; i < _trafficCars.Count; i++) {
         
         if(reference.transform.position.z > (_trafficCars[i].transform.position.z + 15) || reference.transform.position.z < (_trafficCars[i].transform.position.z - (325))){
             ReAlignTraffic(_trafficCars[i]);
         }
         
     }
     
 }

 void ReAlignTraffic(HR_TrafficCar realignableObject){

     if(!realignableObject.gameObject.activeSelf)
         realignableObject.gameObject.SetActive(true);

     int randomLine = Random.Range(0, lines.Length );

     realignableObject.currentLine = randomLine;
     realignableObject.transform.position = new Vector3(lines[randomLine].position.x, realignableObject.transform.position.y, (reference.transform.position.z + (Random.Range(100, 300))));

     switch(HR_GamePlayHandler.Instance.mode){

     case(HR_GamePlayHandler.Mode.OneWay):
             realignableObject.transform.rotation = Quaternion.identity;
             break;
     case(HR_GamePlayHandler.Mode.TwoWay):
         if(realignableObject.transform.position.x <= 0f)
             realignableObject.transform.rotation = Quaternion.identity * Quaternion.Euler(0f, 180f, 0f);
         else
             realignableObject.transform.rotation = Quaternion.identity;
         break;
     case(HR_GamePlayHandler.Mode.TimeAttack):
         realignableObject.transform.rotation = Quaternion.identity;
         break;
     case(HR_GamePlayHandler.Mode.Bomb):
         realignableObject.transform.rotation = Quaternion.identity;
         break;

     }

     realignableObject.SendMessage("OnReAligned");

     if(CheckIfClipping(realignableObject.triggerCollider)){
         realignableObject.gameObject.SetActive(false);
     }

 }

 bool CheckIfClipping(BoxCollider trafficCarBound){

     for (int i = 0; i < _trafficCars.Count; i++) {

         if(!trafficCarBound.transform.IsChildOf(_trafficCars[i].transform) && _trafficCars[i].gameObject.activeSelf){
             if(HR_BoundsExtension.ContainBounds(trafficCarBound.transform, trafficCarBound.bounds, _trafficCars[i].triggerCollider.bounds)){
                 return true;
             }
         }
         
     }

     return false;

 }

}