Error: Reference on this Behavior is Missing.

Questions & Answers
1 
public class Menu : MonoBehaviour 
{
    public bool QuitButton = false;
    public AudioClip Click;
    public Texture2D normalTexture;
    public Texture2D rollOverTexture;
    public int levelToLoad;

    void OnMouseEnter()
    {
        guiTexture.texture = rollOverTexture;
    }

    void OnMouseExit()
    {
        guiTexture.texture = normalTexture;
    }

    void OnMouseDown()
    {
        audio.PlayOneShot(Click);

        if (QuitButton)
        {
            Application.Quit();
        }
        else
        {
            Application.LoadLevel (levelToLoad);
        }
    }
}

This is my simple menu script. It works inside the Editor during testing purposes but after I do a build it never works. I believe it is because I get a "Reference on this Behavior is Missing" Error. Any clues on why?

2

Fixed it, I forgot to add my audio to script, so It then decided that without the Audio the build would not work. Cheers for explaining Statement.