Networking Problem please Help

Hello i made a script that if you press the left mouse button the gun shoots. everything is working perfecly but if i update my script with

 if(!isLocalPlayer)
     {
         return;
     }

it wont work anymore and i don't get an Error.

thats the script without the Network Update.

 #pragma strict
 
 public class Shoot extends UnityEngine.Networking.NetworkBehaviour{
 var Projectil:Rigidbody;
 var reloadeTime:int;
 var isReloading:boolean = false;
 
 function Update () {
     if(Input.GetButtonDown("Fire1") && isReloading == false) 
     {
         Debug.Log("I did a Shoot");
         Instantiate(Projectil, transform.position, transform.rotation);
         isReloading = true;
         Invoke("Reloade", reloadeTime);
     }
 }
 
 function Reloade(){
     isReloading = false;
 }
 }

and this si with the Network Update.

 #pragma strict
 
 public class Shoot extends UnityEngine.Networking.NetworkBehaviour{
 var Projectil:Rigidbody;
 var reloadeTime:int;
 var isReloading:boolean = false;
 
 function Update () {
      if(!isLocalPlayer)
      {
          return;
      }
     if(Input.GetButtonDown("Fire1") && isReloading == false) 
     {
         Debug.Log("I did a Shoot");
         Instantiate(Projectil, transform.position, transform.rotation);
         isReloading = true;
         Invoke("Reloade", reloadeTime);
     }
 }
 
 function Reloade(){
     isReloading = false;
 }
 }

please Help.