C# Unity assembly reference hatası

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityStandardAssets.Vehicles.Car;

public class OwnThirdPersonController : MonoBehaviour {


    public Joystick LeftJoystick;
    public Button Button;
    public TouchField TouchField;

    protected Actions Actions;
    protected PlayerController PlayerController;
    protected Rigidbody Rigidbody;

    protected float CameraAngleY;
    protected float CameraAngleSpeed = 0.1f;
    protected float CameraPosY = 3f;
    protected float CameraPosSpeed = 0.02f;

    // Use this for initialization
    void Start ()
    {
        Actions = GetComponent<Actions>();
        PlayerController = GetComponent<PlayerController>();
        Rigidbody = GetComponent<Rigidbody>();
    }
   
    // Update is called once per frame
    void Update () {

        var input = new Vector3(LeftJoystick.inputVector.x, 0, LeftJoystick.inputVector.y);
        var vel = Quaternion.AngleAxis(CameraAngleY + 180, Vector3.up) * input * 5f;

        Rigidbody.velocity = new Vector3(vel.x, Rigidbody.velocity.y, vel.z);
        transform.rotation = Quaternion.AngleAxis(CameraAngleY + Vector3.SignedAngle(Vector3.forward, input.normalized + Vector3.forward * 0.0001f, Vector3.up) + 180, Vector3.up);

        CameraAngleY += TouchField.TouchDist.x * CameraAngleSpeed;

        Camera.main.transform.position = transform.position + Quaternion.AngleAxis(CameraAngleY, Vector3.up) * new Vector3(0, CameraPosY, 4);
        Camera.main.transform.rotation = Quaternion.LookRotation(transform.position + Vector3.up * 2f - Camera.main.transform.position, Vector3.up);

        if (Rigidbody.velocity.magnitude > 3f)
            Actions.Run();
        else if (Rigidbody.velocity.magnitude > 0.5f)
            Actions.Walk();
        else
            Actions.Stay();
       
    }
}

using UnityEngine.UI;

using UnityStandardAssets;