NullReferenceException：令人沮丧的错误似乎无法找到它

Question

NullReferenceException：未将对象引用设置为对象的实例 SceneControllerEngine.Update（）（在Assets / 02_EngineAR / Scripts / SceneControllerEngine.cs：60）

using UnityEngine;
using System.Collections;

public class SceneControllerEngine : MonoBehaviour {

    //We use this to store all tagged objects in the Scene to be included in the fading effect
    public GameObject[] engineArray;

    //Store a Gameobject reference to the dolphin to disable/enable clicking/touching behaviour
    public GameObject engineClick;

    //The rest of these are public references to objects we are going to switch on and off rather than fade
    public GameObject front;
    public GameObject back;
    public GameObject middle;
    public GameObject lights;

    public AudioSource engineStartFX;

    //Reference to the Fadescript behaviour
    FadeScript fadingScript;


    // Use this for initialization 
    void Start () {

        //Load all tagged objects into an array
        this.engineArray = GameObject.FindGameObjectsWithTag ("EngineScene");
    }

    // Update is called once per frame
    void Update () {

        //FadeOut function

        //Currently uses Keyboard input, change to whatever

        if (Input.GetKey (KeyCode.S)) {
            Debug.Log ("FadeOut Pressed");

            //Switch on objects to be switched

            front.SetActive(false);
            back.SetActive(false);
            middle.SetActive(false);
            lights.SetActive(false);
            engineStartFX.Pause();

            //Disable collider for clicking/touching events
            engineClick.collider.enabled = false;

            //For each loop to take every instance of the FadeScript on each tagged object and trigger the fadeOut boolean
            foreach (GameObject engineScene in engineArray) {
                fadingScript = engineScene.GetComponent<FadeScript> ();
                fadingScript.fadeOut = true;
            }

        }
    }
}

一直在努力解决这个问题，导致更多问题第60行：fadingScript.fadeOut = true;不断抛出错误。我花了很长时间才想到我在圈子里走来走去..