Works when testing in unity but not as a built project

My shooting script works well but it dosen't work at all when i build the project and it runs as a .exe

This is my script: #pragma strict

 /* This is the ammo and firing script
 It fires a projectile untill the ammo runs out.
 This must be attached to an empty game object infront
 of the gun it's being used on
 */
 
 //Variables
 // Bullet or what is going to be shot
 var Projectile : Transform;
 // Fire rate of shooting (Evrey # (0.3 by defualt) seconds, 1 shot is fired)
 static var fireRate : float = 0.3;
 //Time to start shooting
 private var nextFire : float = 2.0;
 //How much ammo the player has
 static var Ammo: int = 30;
 
 // Sound Effect
 var gunfire : AudioClip;
 var reload : AudioClip;
 
 // Booleans
 // Is the Player out of ammo?
 var empty: boolean = false;
 
 function Update () {
 // As Long as the time the game starts and the fire tate = nextFire and is less than Time.time, it'll fire.
 
 if(Input.GetMouseButtonDown(0))
 {
     // If ammo is more than 0 run function Fire
     if(Ammo > 0)
     {
         Fire();
     }
     // Otherwise return
     else
     {
         return;
     }
 }
     if(Input.GetKeyDown("r"))
     // If the R key is pressed run function release
     if(empty)
     {
         Reload();
     }
     // If the ammo is less than or equal to 0 set empty to true
     if(Ammo <= 0)
     {
         empty = true;
     }
     // Otherwise set it to false
     else
     {
         empty = false;
     }
 }
 
 function Fire()
 {
 /*
 Play gunfire audio, add to the next fire time,
 create the bullet and launch it by adding force
 to it's rigidbody, and then substract 1 to the ammo count.
 For it to work, whatever the script is attached to
 needs and audio script component and the bullet needs a
 rigidbody :) :) :)
 */
 audio.PlayOneShot(gunfire);
 nextFire = Time.time + fireRate;
 var shot = Instantiate(Projectile,transform.position, Quaternion.identity);
 shot.rigidbody.AddForce (transform.forward * 3000);
 Ammo--;
 }
 
 function Reload()
 {
 // Reset Ammo to 30
 audio.PlayOneShot(reload);
 Ammo = 30;
 }
 
 function OnGUI()
 {
 // Display the status
     GUI.Box (Rect(Screen.width - 90, 20, 100, 80), "");
     GUI.Label (Rect (Screen.width - 90, 35,90,20), "Ammo: " + Ammo);
     GUI.Label (Rect (Screen.width - 90, 20, 90, 20), "Health: " + PlayerHealth.curHealth);
 
 //If it's empty, show the following display
     if(empty)
     {
         GUI.contentColor = Color.red;
         GUI.Label (Rect (Screen.width - 90, 50, 90, 20), "Reload");
         
     }
 
     }
     
 // Allows the OnGUI function to appear in the editor mode
 @script ExecuteInEditMode()

Note: If you help me fix this problem you can ask for your name in the credits and I may put your name in their if your solution worked.