Script can't find Tagged GameObject

Hello Everyone,
I am making a menu thing where you can place a "block" from a Build Menu. I have made a script that disabled most of the objects on screen when placing it but when i try to place the object or cancel it, nothing responds and there are lots of errors (Object Reference not set to an instance of an object). The problem started when i entered this line of code into the script:

Code (CSharp):

1. MenuThing = GameObject.FindWithTag("MenuButton");

The problem is that the script searches for a GameObject with the tag "MenuButton" but doesn't do anything and the whole script doesn't respond.
How can i fix this? (The script can't find the tagged object)
(Full Script):

Code (CSharp):

1. public Transform objectToPlace;
2. private Camera gameCamera;
3. private GameObject gameCamera3;
4. private GameObject MenuThing;
5.  
6. void Update() {
7.  
8.       MenuThing = GameObject.FindWithTag("MenuButton");
9.        gameCamera3 = GameObject.FindWithTag("CameraTag");
10.        gameCamera = gameCamera3.GetComponent<Camera>();
11.      Ray ray = gameCamera.ScreenPointToRay (Input.mousePosition);
12.      RaycastHit hitInfo;
13.  
14.       if (Physics.Raycast (ray, out hitInfo)) {
15.  
16.            objectToPlace.position = hitInfo.point;
17.  
18.       if (Input.GetMouseButton(0))
19.         {
20.       MenuThing.SetActive(true);
21.         objectToPlace.GetComponent<BuildingFollow2>().enabled = false;
22.          objectToPlace.GetComponent<RotationBuilding>().enabled = false;
23.      
24.           }
25.       if (Input.GetKey(KeyCode.Escape))
26.       {
27.         MenuThing.SetActive(true);
28.         Destroy(gameObject);
29.    
30.     }
31.   }
32. }
33. }
34.  

 

Is your menu(button) active if you do that call otherwise the method will return null, because it can only find active objects.

 

The Button isn't active. Is there any way activate it another way?

 

Fixed it by moving the deactivating to the same script and referencing there