My script does not work anymore

I have used this script and everything worked fine. But now does not work, I can't understand what happened. I think it is an error on Unity. What do you think?

Code (JavaScript):

1. #pragma strict
2.  
3.      var mainPrefab : GameObject;
4.      var secondPrefab : GameObject;
5.      var thirdPrefab : GameObject;
6.      var fourthPrefab : GameObject;
7.    
8.  
9.  
10.    
11.      function OnTriggerEnter2D(other:Collider2D)
12.     {
13.     switch( Random.Range(0,4))
14.     {
15.             case 01:secondPrefab.transform.position.x = mainPrefab.transform.position.x +(35); secondPrefab.transform.position.y = -1.7; Debug.Log("One");  break;
16.             case 02:thirdPrefab.transform.position.x = mainPrefab.transform.position.x +(35); thirdPrefab.transform.position.y = -1.7; Debug.Log("Two"); break;    
17.             case 03:fourthPrefab.transform.position.x = mainPrefab.transform.position.x +(35); fourthPrefab.transform.position.y= -1.7; Debug.Log("three");  break;
18.          
19.     }
20.     }
21.  
22.  

I make a 2D Endless Runner. I want spawn the platform where the character run. But now doesn't work anymore.

 

Can you explain it , any errors getting while the scene is played ?

 

while my scene is playing everything is ok. But the script looks like desactivate. I do not know how to explain it. Two weeks ago that script worked perfectly