Array index is out of range HELP

Hello I am getting the error “IndexOutOfRangeException: Array index is out of range.” and I don’t know how to fix as it was working before but just started giving me this error yesterday. HELP

public class LevelSelect1 : MonoBehaviour {

public string level1;
public string level2;
public string level3;
public string level4;
public string level5;
public string level6;
public string level7;
public string level8;
public string level9;
public string level10;
public string level11;
public string level12;
public string back;
public LevelSelectManager Unlocked;

public float a;
public float quality;
public GameObject Fade;
private string LevelToLoad;

void Start(){
	Unlocked = FindObjectOfType <LevelSelectManager>();
}

void Update () {
	
	if (LevelToLoad != null) {
		while (a < 1) {
			a += quality * Time.deltaTime;
			Fade.GetComponent<SpriteRenderer> ().color = new Color (0, 0, 0, a);
			return;
		}
		Application.LoadLevel (LevelToLoad);
	}
		
}

public void Level1() {
	if (Unlocked.LevelUnlocked[0])
		LevelToLoad = level1;
}
public void Level2() {
	if (Unlocked.LevelUnlocked[1])
		LevelToLoad = level2;
}
public void Level3() {
	if(Unlocked.LevelUnlocked[2])
		LevelToLoad = level3;
}
public void Level4() {
	if(Unlocked.LevelUnlocked[3])
		LevelToLoad = level4;
}
public void Level5() {
	if(Unlocked.LevelUnlocked[4])
		LevelToLoad = level5;
}
public void Level6() {
	if(Unlocked.LevelUnlocked[5])
		LevelToLoad = level6;
}
public void Level7() {
	if(Unlocked.LevelUnlocked[6])
		LevelToLoad = level7;
}
public void Level8() {
	if(Unlocked.LevelUnlocked[7])
		LevelToLoad = level8;
}
public void Level9() {
	if(Unlocked.LevelUnlocked[8])
		LevelToLoad = level9;
}
public void Level10() {
	if(Unlocked.LevelUnlocked[9])
		LevelToLoad = level10;
}
public void Level11() {
	if(Unlocked.LevelUnlocked[10])
		LevelToLoad = level11;
}
public void Level12() {
	if(Unlocked.LevelUnlocked[11])
		LevelToLoad = level12;
}
public void Back() {
	LevelToLoad = back;
}

}

I don’t see where you’ve declared or defined your array. Did you populate the LevelUnlocked array somewhere that you didn’t post here? Print the array to console and look at what’s in it.