C# object reference not set to an instance of an object CS86

Hi I am having issues with this code I receive an error on line 86 or specifically: Bounds bounds = collider.bounds; I am able to start my game but the player will not move left or right. Also I have created a Layer for the Player and the Platforms (which are layered as Obstacle) and the platforms have a Box Collider 2D. Any and all help is greatly appreciated. The full code is: using UnityEngine; using System.Collections;

[RequireComponent (typeof (BoxCollider2D))] public class Controller2D : MonoBehaviour {

 public LayerMask collisionMask;

 const float skinWidth = .015f;
 public int horizontalRayCount = 4;
 public int verticalRayCount = 4;

 float horizontalRaySpacing;
 float verticalRaySpacing;

 BoxCollider2D collider;
 RaycastOrigins raycastOrigins;

 void Start() {
     collider = GetComponent<BoxCollider2D> ();
     CalculateRaySpacing ();
 }

 public void Move(Vector3 velocity) {
     UpdateRaycastOrigins ();
     if (velocity.x != 0) {
         HorizontalCollisions (ref velocity);
     }
     if (velocity.y != 0) {
         VerticalCollisions (ref velocity);
     }

     transform.Translate (velocity);
 }

 void HorizontalCollisions(ref Vector3 velocity) 
 {
     float directionX = Mathf.Sign (velocity.x);
     float rayLength = Mathf.Abs (velocity.x) + skinWidth;

     for (int i = 0; i < horizontalRayCount; i ++) 
     {
         Vector2 rayOrigin = (directionX == -1)?raycastOrigins.bottomLeft:raycastOrigins.bottomRight;
         rayOrigin += Vector2.up * (horizontalRaySpacing * i);
         RaycastHit2D hit = Physics2D.Raycast(rayOrigin, Vector2.right * directionX, rayLength, collisionMask);

         Debug.DrawRay(rayOrigin, Vector2.right * directionX * rayLength,Color.red);

         if (hit) 
         {
             velocity.x = (hit.distance - skinWidth) * directionX;
             rayLength = hit.distance;
         }
     }
 }

 void VerticalCollisions(ref Vector3 velocity) 
 {
     float directionY = Mathf.Sign (velocity.y);
     float rayLength = Mathf.Abs (velocity.y) + skinWidth;

     for (int i = 0; i < verticalRayCount; i ++) 
     {
         Vector2 rayOrigin = (directionY == -1)?raycastOrigins.bottomLeft:raycastOrigins.topLeft;
         rayOrigin += Vector2.right * (verticalRaySpacing * i + velocity.x);
         RaycastHit2D hit = Physics2D.Raycast(rayOrigin, Vector2.up * directionY, rayLength, collisionMask);

         Debug.DrawRay(rayOrigin, Vector2.up * directionY * rayLength,Color.red);

         if (hit) 
         {
             velocity.y = (hit.distance - skinWidth) * directionY;
             rayLength = hit.distance;
         }
     }
 }

 void UpdateRaycastOrigins() 
 {
     Bounds bounds = collider.bounds;
     bounds.Expand (skinWidth * -2);

     raycastOrigins.bottomLeft = new Vector2 (bounds.min.x, bounds.min.y);
     raycastOrigins.bottomRight = new Vector2 (bounds.max.x, bounds.min.y);
     raycastOrigins.topLeft = new Vector2 (bounds.min.x, bounds.max.y);
     raycastOrigins.topRight = new Vector2 (bounds.max.x, bounds.max.y);
 }

 void CalculateRaySpacing() 
 {
     Bounds bounds = collider.bounds;
     bounds.Expand (skinWidth * -2);

     horizontalRayCount = Mathf.Clamp (horizontalRayCount, 2, int.MaxValue);
     verticalRayCount = Mathf.Clamp (verticalRayCount, 2, int.MaxValue);

     horizontalRaySpacing = bounds.size.y / (horizontalRayCount - 1);
     verticalRaySpacing = bounds.size.x / (verticalRayCount - 1);
 }

 struct RaycastOrigins 
 {
     public Vector2 topLeft, topRight;
     public Vector2 bottomLeft, bottomRight;
 }

}