UnityEngine.MovieTexure is required access, Help?

this is the script for playing the movie on gameobject

 #pragma strict
 
 RequireComponent(AudioSource);
 
 // Assigns a movie texture to the current material and plays it.
 
 var movTexture : MovieTexture;
 
 function Start () {
     GetComponent.<Renderer>().material.mainTexture = movTexture;    
     var aud: AudioSource = GetComponent.<AudioSource>();
     aud.clip = MovieTexture.audioClip();
     movTexture.Play();
     aud.Play();
 }

aud.clip = MovieTexture.audioClip(); keeps coming up with error: UnityEngine.MovieTexture is required access?

how do i fix this? thanks