level never loads again after quitting to the menu

So my start game button works fine, but after quitting out of the game back to the menu, it doesnt work??? this even happens when i start at the level! what is going on?

EDIT:

Each time, NO errors or ANYTHING. just doesnt load if i quitted out.

So move your PlayButton anywhere else.

Change the script to this :

public void LoadLevel()
    {
        StartCoroutine(LoadLevelCoroutine(0.1f));
    }

    IEnumerator LoadLevelCoroutine(float waitingTime)
    {
        yield return new WaitForSeconds(waitingTime);
        Application.LoadLevel("Empty Graves");
    }
}

and call LoadLevel as the first method of your PlayButton (the game object)