Launch a method from another class

Hello, i've got a problem in my code, i use Unity and i have 2 C# classes , I want to call the method "OnButtonPressed(VirtualButtonBehaviour vb)" from the second one called ObjectHighlighter.cs , sorry i'am pretty new on C# but i need to find a solution , i'am doing something wrong on the second class i've got an error once i call the method from the second class wich is:

 

"NullReferenceException: Object reference not set to an instance of an object

ObjectHighlighter.Update () (at Assets/Scripts/ObjectHighlighter.cs:45)"

 

Any ideas ? Thank you !

 

- My First class:

 

public class VB_Anim : MonoBehaviour, IVirtualButtonEventHandler {

public static GameObject vbBtnObj;

public Animator immoAni;

// Use this for initialization

void Start () {

vbBtnObj = GameObject.Find("Vb_Rotate");

vbBtnObj.GetComponent().RegisterEventHandler(this);

immoAni.GetComponent();

}

public void OnButtonPressed(VirtualButtonBehaviour vb)

{

immoAni.enabled = true;

immoAni.Play("immo_rotate_animation");

Debug.Log("BTN Pressed the Animation is running");

}

public void OnButtonReleased(VirtualButtonBehaviour vb)

{

immoAni.enabled = false;

}

// Update is called once per frame

void Update () {

}

}

-Here is my second class called ObjectHighlighter.cs

 

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

public class ObjectHighlighter : MonoBehaviour

{

public Animator anim;

public static VirtualButtonBehaviour vbBtnObj;

public Animator immoAni;

public VB_Anim vbscript;

// initialization

void Start()

{

}

void Update () {

foreach (Touch touch in Input.touches)

{

Debug.Log("ok...");

if (touch.phase == TouchPhase.Began)

{

Ray ray = Camera.main.ScreenPointToRay (Input.GetTouch(0).position);

RaycastHit hit = new RaycastHit();

if (Physics.Raycast(ray, out hit, 100000))

{

vbscript.OnButtonPressed(vbBtnObj);

}

}

}

}

}