FadeInOut problem

Hello, currently i have this code for a FadeInOut animation between my levels:

using UnityEngine;

public class CameraFade : MonoBehaviour { // ---------------------------------------- // PUBLIC FIELDS // ----------------------------------------

 // Alpha start value
 public float startAlpha = 1;

 // Texture used for fading
 public Texture2D fadeTexture;

 // Default time a fade takes in seconds
 public float fadeDuration = 2;

 // Depth of the gui element
 public int guiDepth = -1000;

 // Fade into scene at start
 public bool fadeIntoScene = true;

 // ---------------------------------------- 
 //     PRIVATE FIELDS
 // ----------------------------------------

 // Current alpha of the texture
 private float currentAlpha = 1;

 // Current duration of the fade
 private float currentDuration;

 // Direction of the fade
 private int fadeDirection = -1;

 // Fade alpha to
 private float targetAlpha = 0;

 // Alpha difference
 private float alphaDifference = 0;

 // Style for background tiling
 private GUIStyle backgroundStyle = new GUIStyle();
 private Texture2D dummyTex;

 // Color object for alpha setting
 Color alphaColor = new Color();

 // ---------------------------------------- 
 //     FADE METHODS
 // ----------------------------------------

 public void FadeIn(float duration, float to)
 {
     // Set fade duration
     currentDuration = duration;
     // Set target alpha
     targetAlpha = to;
     // Difference
     alphaDifference = Mathf.Clamp01(currentAlpha - targetAlpha);
     // Set direction to Fade in
     fadeDirection = -1;
     //Check to see if currentAlpha is set to 1.  It will need to be 1 to fade properly
     }

 public void FadeIn()
 {
     FadeIn(fadeDuration, 0);
 }

 public void FadeIn(float duration)
 {
     FadeIn(duration, 0);
 }

 public void FadeOut(float duration, float to)
 {
     // Set fade duration
     currentDuration = duration;
     // Set target alpha
     targetAlpha = to;
     // Difference
     alphaDifference = Mathf.Clamp01(targetAlpha - currentAlpha);
     // Set direction to fade out
     fadeDirection = 1;
     //Check to see if currentAlpha is set to 1.  It will need to be 1 to fade properly
     }

 public void FadeOut()
 {
     FadeOut(fadeDuration, 1);
 }

 public void FadeOut(float duration)
 {
     FadeOut(duration, 1);
 }

 // ---------------------------------------- 
 //     STATIC FADING FOR MAIN CAMERA
 // ----------------------------------------

 public static void FadeInMain(float duration, float to)
 {
     GetInstance().FadeIn(duration, to);
 }

 public static void FadeInMain()
 {
     GetInstance().FadeIn();
 }

 public static void FadeInMain(float duration)
 {
     GetInstance().FadeIn(duration);
 }

 public static void FadeOutMain(float duration, float to)
 {
     GetInstance().FadeOut(duration, to);
 }

 public static void FadeOutMain()
 {
     GetInstance().FadeOut();
 }

 public static void FadeOutMain(float duration)
 {
     GetInstance().FadeOut(duration);
 }

 // Get script fom Camera
 public static CameraFade GetInstance()
 {
     // Get Script
     CameraFade fader = (CameraFade)Camera.main.GetComponent("FadeInOut");
     // Check if script exists
     if (fader == null)
     {
         Debug.LogError("No FadeInOut attached to the main camera.");
     }
     return fader;
 }

 // ---------------------------------------- 
 //     SCENE FADEIN
 // ----------------------------------------

 public void Start()
 {
     Debug.Log("Starting FadeInOut");

     dummyTex = new Texture2D(1, 1);
     dummyTex.SetPixel(0, 0, Color.clear);
     backgroundStyle.normal.background = fadeTexture;
     currentAlpha = startAlpha;
     if (fadeIntoScene)
     {
         FadeIn();
     }
 }

 // ---------------------------------------- 
 //     FADING METHOD
 // ----------------------------------------

 public void OnGUI()
 {
     // Fade alpha if active
     if ((fadeDirection == -1 && currentAlpha > targetAlpha) ||
         (fadeDirection == 1 && currentAlpha < targetAlpha))
     {
         // Advance fade by fraction of full fade time
         currentAlpha += (fadeDirection * alphaDifference) * (Time.deltaTime / currentDuration);
         // Clamp to 0-1
         currentAlpha = Mathf.Clamp01(currentAlpha);
     }

     // Draw only if not transculent
     if (currentAlpha > 0)
     {
         // Draw texture at depth
         alphaColor.a = currentAlpha;
         GUI.color = alphaColor;
         GUI.depth = guiDepth;
         GUI.Label(new Rect(-10, -10, Screen.width + 10, Screen.height + 10), dummyTex, backgroundStyle);
     }
 }

} The problem is that when i go back to my main menu, the screen remains black but the music is playing in the background. I assume this is caused by the Alpha but i don't know what to do. I have this script from : http://wiki.unity3d.com/index.php?title=FadeInOut#Introduction_5 The solution is this :
//Check to see if currentAlpha is set to 1. It will need to be 1 to fade properly if (currentAlpha != 1){ currentAlpha = 1;
} But i don't know where to put it to work well, i tried in the Fade in and Fade out but still the same problem. Thanks!