Move Texture From Plane To GUI And Back

Hi,

I have several planes moving in straight lines across my scene. Each plane has its assigned texture. What I want to be able to do is, on clicking the plane, the texture is displayed in a screen centered static GUI. On clicking this GUI, the texture is re-displayed on the plane, at whatever point the plane has since moved to.

This is my script, which does about half the job, but fails to consistantly react to clicks at all and, though it will clear the GUI texture, it won't then re-display it as required.

tia for any help.

 var url : String;
 var baseurl = "www.someurl.com/filename";
 var filext = ".ogg";
 var num : int;
 var thisTex : MovieTexture;
 var movTexture : MovieTexture;
 var obSpeed : int;
 var isGUI : boolean = false;
 
 
 
 function zoomToGUI(){
     isGUI = true;
     while (!movTexture.isReadyToPlay)
         yield;
     obSpeed = 0;
     guiTexture.enabled = true;
     guiTexture.texture = movTexture;
     transform.Translate(obSpeed * Vector3.up * Time.deltaTime * 2);
     transform.localScale = Vector3 (0,0,0);
     transform.position = Vector3 (0.5,0.5,0);
     guiTexture.pixelInset.xMin = -movTexture.width / 2;
     guiTexture.pixelInset.xMax = movTexture.width / 2;
     guiTexture.pixelInset.yMin = -movTexture.height / 2;
     guiTexture.pixelInset.yMax = movTexture.height / 2;
     // Play movie
     movTexture.Play();
 }
 function playVid(){
     isGUI = false;
     var www = new WWW(url);
     renderer.enabled = false;
     // Make sure the movie is ready to start before we start playing
     movTexture = www.movie;
     while (!movTexture.isReadyToPlay)
         yield;
     obSpeed = 2;
     movTexture.loop = true;
     renderer.enabled = true;
     renderer.material.mainTexture = movTexture;
     movTexture.Play();
     if(movTexture.isPlaying){
         // do nothing
     }else{
         yield WaitForSeconds(5);
         renderer.enabled = false;
     }
 }
 
 function OnMouseDown(){
     if(isGUI == false){
         zoomToGUI();
     }else{
         guiTexture.enabled = false;
         playVid();
     }
 }
 
 function Start () {
     url = baseurl + num + filext;
     playVid();
     // Start download
 }
 
 function Update() {
     transform.Translate(obSpeed * Vector3.up * Time.deltaTime);
 }
 @script RequireComponent (GUITexture)