Array Index is Out of Range?

Questions & Answers
1

I seem to be getting this error:

IndexOutOfRangeException: Array index is out of range.
Footstep.WalkOnWood () (at Assets/_Scripts/Footstep.cs:59)
Footstep.OnControllerColliderHit (UnityEngine.ControllerColliderHit hit) (at Assets/_Scripts/Footstep.cs:29)
UnityEngine.CharacterController:Move(Vector3)
CharacterMotor:UpdateFunction() (at Assets/Standard Assets/Character Controllers/Sources/Scripts/CharacterMotor.js:229)
CharacterMotor:FixedUpdate() (at Assets/Standard Assets/Character Controllers/Sources/Scripts/CharacterMotor.js:331)

When I walk on Concrete, it plays the audio fine with no errors. But when I transition from walking on Concrete to Wood, I instantly get this error. Can anybody tell me why? Here’s the script:

using UnityEngine;
using System.Collections;

public class Footstep : MonoBehaviour {

public CharacterController controller; 
public AudioClip[] concrete; 
public AudioClip[] wood; 
public AudioClip[] dirt; 
public AudioClip[] metal; 
public AudioClip[] glass; 
public AudioClip[] sand; 
public AudioClip[] snow; 
public AudioClip[] floor; 
public AudioClip[] grass;

private bool step = true; 
float audioStepLengthWalk = 0.7f; 
float audioStepLengthRun = 0.7f;

void OnControllerColliderHit ( ControllerColliderHit hit) {
	if (controller.isGrounded && controller.velocity.magnitude < 10 && controller.velocity.magnitude > 5 && hit.gameObject.tag == "Untagged" && step == true ) {
		WalkOnConcrete();
	} else if (controller.isGrounded && controller.velocity.magnitude > 8 && hit.gameObject.tag == "Concrete" && step == true || controller.isGrounded && controller.velocity.magnitude > 10 && hit.gameObject.tag == "Untagged" && step == true) {
		RunOnConcrete();
	}

	if (controller.isGrounded && controller.velocity.magnitude < 10 && controller.velocity.magnitude > 5 && hit.gameObject.tag == "Wood" && step == true ) {
			WalkOnWood();
		} else if (controller.isGrounded && controller.velocity.magnitude > 8 && hit.gameObject.tag == "Wood" && step == true || controller.isGrounded && controller.velocity.magnitude > 10 && hit.gameObject.tag == "Untagged" && step == true) {
			RunOnWood();
		}
}

IEnumerator WaitForFootSteps(float stepsLength) { 
	step = false; 
	yield return new WaitForSeconds(stepsLength); 
	step = true; } 

/////////////////////////////////// CONCRETE //////////////////////////////////////// 

	void WalkOnConcrete() {
		audio.clip = concrete[Random.Range(0, concrete.Length)];
		audio.volume = 0.65f;
		audio.Play();
		StartCoroutine(WaitForFootSteps(audioStepLengthWalk));
	}

	void RunOnConcrete() {
		audio.clip = concrete[Random.Range(0, concrete.Length)];
		audio.volume = 0.65f;
		audio.Play();
		StartCoroutine(WaitForFootSteps(audioStepLengthWalk));
	}

	/////////////////////////////////// Wood //////////////////////////////////////// 

	void WalkOnWood() {
		audio.clip = wood[Random.Range(0, concrete.Length)];
		audio.volume = 0.75f;
		audio.Play();
		StartCoroutine(WaitForFootSteps(audioStepLengthWalk));
	}

	void RunOnWood() {
		audio.clip = wood[Random.Range(0, concrete.Length)];
		audio.volume = 0.75f;
		audio.Play();
		StartCoroutine(WaitForFootSteps(audioStepLengthWalk));
	}
}
2

on WalkOnWood and RunOnWood methods, use the length of wood, not concrete.

audio.clip = wood[Random.Range(0, wood.Length)];