For Loop isn't working properly!

I've made a script such that it instantiates an object randomly choosing between 2 objects. But, now the For loop doesn't work. Here's the script:

 var virusPrefab : Transform;
 var filePrefab : Transform;
 var position: Vector3;
 var virusesKilled : int = 0;
 var myResult : result;
 var randomVirus : float;
 var randomFiles : float;
 var randomTotal : float;
 var virusOrFile : float;
 
 function Start(){
     var myResultObject : GameObject = GameObject.FindGameObjectWithTag("Finish");
     if (myResultObject != null) {
             myResult = myResultObject.GetComponent(result);
     }
     randomTotal = Random.Range(45, 60);
     randomVirus = randomTotal - 25;
     randomFiles = randomTotal - randomVirus;
 }
 
 function Update(){
     position = Vector3(Random.Range(0.5, 2), Random.Range(-2, 2), 6.351526);
     
     myResult.total = randomTotal;
     myResult.totalVirus = randomVirus;
     myResult.score = virusesKilled;    
     myResult.totalFiles = randomFiles;
 }
  

 //The For loop section starts from here...

 yield WaitForSeconds(3);
 for (var i : int = 0;i < randomTotal; i++) {
     virusOrFile = Random.Range(0, 1);//To choose between the 2 objects
         
     if(virusOrFile == 0){
         var file : Transform = Instantiate(filePrefab, position, Quaternion.identity);
         file.transform.parent = GameObject.Find("files").transform;
     }    
     
     if(virusOrFile == 1){
         var virus : Transform = Instantiate(virusPrefab, position, Quaternion.identity);
         virus.transform.parent = GameObject.Find("viruses").transform;
     }
     yield WaitForSeconds(1);
 }

 //And ends here

 if(virusesKilled < 15){
     myResult.enabled = true;
     myResult.OnGUI();
     Application.LoadLevel("gameOver");
 }
 
 function AddScore(score : int){
     virusesKilled += score;
     Debug.Log("Score is : " + virusesKilled);
     return virusesKilled;
 }
 
 if(virusesKilled > 15){
     myResult.enabled = true;
     myResult.OnGUI();
 }

I decided to add all of the script here, if you see any variable problem.

Before, I have written the loop like this:

 yield WaitForSeconds(3);
 for (var i : int = 0;i < randomTotal; i++) {    
       var virus : Transform = Instantiate(virusPrefab, position, Quaternion.identity);
     virus.transform.parent = GameObject.Find("viruses").transform;
 
     yield WaitForSeconds(1);
 }

And it worked fine, but now after randomly choosing between two objects the loop isn't functioning!

Please help me...