Null Reference Expantion

Hello there, i have two kind of scripts. One is board another is animation, if i play my animation seperately its working fine. if i call that animation to board script, it says null reference expantion, i cant clearly with words so i will add my scripts here.

Animation Coding:

using UnityEngine; using System.Collections;

public class AnimationObject : MonoBehaviour {

 public bool showButton = false;

 void start()
 {

 }

 public void OnGUI()
 {
     if(showButton)
     {
         if(GUI.Button(new Rect(50,30,80,30),"Dice Roll"))
         {
             animation.Play("Take 001");
         }
     }
 }

 public void Update()
 {
     showButton = true;
 }

}

Board Coding:

using UnityEngine; using System.Collections;

[ExecuteInEditMode] [RequireComponent(typeof(MeshFilter))] [RequireComponent(typeof(MeshRenderer))] [RequireComponent(typeof(MeshCollider))]

public class Board : MonoBehaviour { public int size_x=10; public int size_z=10; public float tileSize=1.0f; public AnimationObject getFunction;

 // Use this for initialization
 void Start () 
 {
     CreateBoard();
 }

 public void CreateBoard()
 {
     int numTiles        =    size_x * size_z;
     int numTris            =    numTiles * 2;

     int vsize_x            =    size_x + 1;
     int vsize_z            =    size_z + 1;
     int numVerts        =    vsize_x * vsize_z;

     Vector3[] vertices    =    new Vector3[numVerts];
     Vector3[] normals    =    new Vector3[numVerts];
     Vector2[] uv        =    new Vector2[numVerts];

     int[] triangles        =    new int[numTris*3];

     int x,z;
     for(z=0; z < vsize_z; z++)
     {
         for(x=0 ; x < vsize_x; x++)
         {
             vertices[ z * vsize_x + x]=new Vector3(x * tileSize, 0 , z*tileSize);
             normals[z * vsize_x + x]=Vector3.up;
             uv[z * vsize_x + x]=new Vector2((float)x / size_x,(float)z / size_z);
         }
     }

     for(z=0; z < size_z; z++)
     {
         for(x=0 ;x < size_x; x++)
         {
             int squareIndex    =    z * size_x + x;
             int trioffset    =    squareIndex * 6;
             triangles[trioffset + 0]    =    z * vsize_x + x + 0;
             triangles[trioffset + 2]    =    z * vsize_x + x + vsize_x + 1;
             triangles[trioffset + 1]    =    z * vsize_x + x + vsize_x + 0;

             triangles[trioffset + 3]    =    z * vsize_x + x + 0;
             triangles[trioffset + 5]    =    z * vsize_x + x + 1;
             triangles[trioffset + 4]    =    z * vsize_x + x + vsize_x + 1;
         }
     }

     Mesh mesh        =    new Mesh();
     mesh.vertices    =    vertices;
     mesh.triangles    =    triangles;
     mesh.normals    =    normals;
     mesh.uv            =    uv;

     MeshFilter mesh_filter        =    GetComponent<MeshFilter>();
     MeshRenderer mesh_renderer    =    GetComponent<MeshRenderer>();
     MeshCollider mesh_collider    =    GetComponent<MeshCollider>();

     mesh_collider.sharedMesh = mesh;
     mesh_filter.mesh    =    mesh;
 }
 
 // Update is called once per frame
 void Update () 
 {
     getFunction.OnGUI();
     getFunction.Update();
 }

}