What's grong with this script?

Nothing is grong with the script. I have no idea where you got this version of my script, but for the sake of answering and closing this question, you need to add your own solution for when all the papers are collected. It is clear in the GUI when all the papers are collected. Anyway, here is a more detailed version which clearly indicates what to do when the win condition has been reached :

 #pragma strict
 @script RequireComponent ( AudioSource )
 var papers : int = 0;
 var papersToWin = 5;
 var distanceToPaper : float = 2.5;
 public var paperPickup : AudioClip;
 
 function Start ()
 {
     Screen.lockCursor = true;
 }
 
 function Update ()
 {
     if(Input.GetMouseButtonDown (0) || Input.GetKeyDown (KeyCode.E))
     {
         var ray = Camera.main.ScreenPointToRay(Vector3(Screen.width * 0.5, Screen.height * 0.5, 0.0));
         var hit : RaycastHit;
 
         if(Physics.Raycast(ray, hit, distanceToPaper))
         {
             if(hit.collider.gameObject.name == "Paper")
             {
                 papers += 1;
                 audio.PlayClipAtPoint(paperPickup, transform.position);
                 Destroy(hit.collider.gameObject);
             }
             
             // check if all papers have been collected
             if ( papers >= papersToWin )
             {
                 Debug.Log( "All Papers Collected!" );
                 
                 // ** ADD YOUR WIN CONDITION HERE **
                 // probably load a new scene, eg
                 // Application.LoadLevel( "WinScene" );
             }
         }
     }
 }
 
 function OnGUI ()
 {
     if(papers < papersToWin)
     {
         GUI.Box(Rect((Screen.width * 0.5) -60, 10, 120, 25), " " + papers.ToString() + " papers");
     }
     else
         GUI.Box(Rect((Screen.width/2) - 100, 10, 200, 35), "All Papers Collected!");
 }

For further information, you can watch one of the many videos I have made on collecting papers (and I thought this had stopped haunting me...)

• Collect papers using Raycast

• Collect Papers using SphereCast

• implementation from the new guide

• new guide full playlist with win and lose scenes near the end