hi, am getting these two errors

UnityException: Tag: Moveable is not defined!
MoveRight.Start () (at Assets/MoveRight.cs:19)

NullReferenceException
MoveRight.Update () (at Assets/MoveRight.cs:67)

with the following code

using UnityEngine;
using System.Collections;

public class MoveLeft : MonoBehaviour
{
public Vector3 moveSpeed = new Vector3();
private bool moving = false;
private GameObject scene; //array of game objects that conform the scene
private GameObject bg;

// Use this for initialization
void Start()
{
	scene = GameObject.FindGameObjectsWithTag("Moveable"); //Game objects with Moveable tag
	bg = GameObject.Find("Background"); //Game Background
}

// Update is called once per frame
void Update()
{
	/* Detect touch */
	if (Application.platform == RuntimePlatform.Android)
	{
		if (Input.touchCount > 0)
		{
			if (Input.GetTouch(0).phase == TouchPhase.Began)
			{ 
				CheckTouch(Input.GetTouch(0).position, "began");
			} else if (Input.GetTouch(0).phase == TouchPhase.Ended)
			{
				CheckTouch(Input.GetTouch(0).position, "ended");
			}
		}
	}
	
	if (Application.platform == RuntimePlatform.OSXEditor)
	{
		if (Input.GetMouseButtonDown(0))
		{
			CheckTouch(Input.mousePosition, "began");
		}
		
		if (Input.GetMouseButtonUp(0))
		{
			CheckTouch(Input.mousePosition, "ended");
		}
	}
	
	// Move if button is pressed
	if (moving && bg.transform.position.x < 4.82f)
	{
		for (int i = 0; i < scene.Length; i++)
		{
			if (scene  *!= null)*
  •   		{*
    

_ scene .transform.position += moveSpeed;_
* }*
* }*
* }*
* }*

* void CheckTouch(Vector3 pos, string phase)*
* {*
* Vector3 wp = Camera.main.ScreenToWorldPoint(pos);*
* Vector2 touchPos = new Vector2(wp.x, wp.y);*
* Collider2D hit = Physics2D.OverlapPoint(touchPos);*

* if (hit.gameObject.name == “LeftButton” && hit && phase == “began”)*
* {*
* moving = true;*
* }*

* if (hit.gameObject.name == “LeftButton” && hit && phase == “ended”)*
* {*
* moving = false;*
* }*
* }*
}

The error message is pretty explicit - you haven’t got a tag called “Moveable” defined. Therefore scene is null, which is what the second error tells you.