Object Click launching Movie on GUI Texture

I have different clickable objects in my scene and would like to show a short movie (stored online, accessed via url) on a full screen GUI texture after the object was clicked. Upon clip end or a second click, the GUI should disappear and the camera returning to show the scene.

I used the PlayVideoFit script and put it on the main camera, then attempted to call its LaunchFunction from my CallScriptOnClick script attached to the clickable object. Despite searching the forums I have not found a solution that makes this work and would be very happy to get some help, a hint, or suggestion how this could be done in another way.

 // Created by DimasTheDriver in 19/Apr/2011                                              //
 // Available at:      http://www.41post.com/?p=3687                                     //
 
 
 using UnityEngine;
 using System.Collections;
 
 [RequireComponent (typeof (GUITexture))]
 [RequireComponent (typeof (AudioSource))]
 
 public class PlayVideoFit : MonoBehaviour 
 {
     //the GUI texture
     public GUITexture videoGUItex;
     //the Movie texture
     public MovieTexture mTex;
     //the AudioSource
     public AudioSource movieAS;
     //the movie name inside the resources folder
     public string movieName;
 
     void Awake()
     {
         //get the attached GUITexture
         videoGUItex = this.GetComponent<GUITexture>();
         //get the attached AudioSource
         movieAS = this.GetComponent<AudioSource>();
         //load the movie texture from the resources folder
         mTex = (MovieTexture)Resources.Load(movieName);
         //set the AudioSource clip to be the same as the movie texture audio clip
         movieAS.clip = mTex.audioClip;
         //fullscreen with vertical borders
         float newWidth = -(Screen.width-(Screen.height*(mTex.width/(float)mTex.height)));
         float xOffset = (Screen.width - newWidth)/2;
         videoGUItex.pixelInset = new Rect(xOffset, -Screen.height/2,newWidth,0);
     }
 
     //On Script Start
     public void LaunchFunction ()
     {
         //set the videoGUItex.texture to be the same as mTex
         videoGUItex.texture = mTex;
         //Plays the movie
         mTex.Play();
         //plays the audio from the movie
         movieAS.Play(); 
     }
     
 }
 

Combined with the CallScriptOnClick, which is added to the clickable object.

 using UnityEngine;
 using System.Collections;
 
 public class CallScriptOnClick : MonoBehaviour
 {    
     /* reference to the PlayVideoFit script */
     public PlayVideoFit Menu; 
     private PlayVideoFit myPlayVideoFit;
 
     /* attempt of calling LaunchFunction in PlayVideoFit script */
     void OnMouseDown ()
         {
         Debug.Log ("Launch Video");
         myPlayVideoFit = new PlayVideoFit ();
         myPlayVideoFit.LaunchFunction ();
         }
 }