NullReferenceException

Good day. I recently ran into a problem. I'm creating a multiplayer game, and it returns the following error when i click a button:

NullReferenceException: Object reference not set to an instance of an object
QuickMenu.QuickMenu () (at Assets/Game/GameAssets/Scripts/QuickMenu.js:53)
CompilerGenerated.$adaptor$__BasicComputer_OnGUI$callable0$61_113__$WindowFunction$0.Invoke (Int32 id)
UnityEngine.GUILayout+LayoutedWindow.DoWindow (Int32 windowID) (at C:/BuildAgent/work/6bc5f79e0a4296d6/Runtime/ExportGenerated/Editor/GUILayout.cs:307)
UnityEngine.GUI+_Window.Do () (at C:/BuildAgent/work/6bc5f79e0a4296d6/Runtime/ExportGenerated/Editor/GUI.cs:985)
UnityEngine.GUI.BeginWindows (UnityEngine.Event e, Int32 skinMode, UnityEngine.IDList idlist, Int32 editorWindowInstanceID) (at C:/BuildAgent/work/6bc5f79e0a4296d6/Runtime/ExportGenerated/Editor/GUI.cs:1205)

Here is the code on the button:

if (GUILayout.Button("Get moneyz")) {
 theScoreBoard.LocalPlayerHasKilled();
}

And here is the giefmoney function:

function giefmoney(){
    var coin : int = 5;
    for (var playerInstance : FPSPlayerNode in gameSetupScript.playerList) {
        if (Network.player == playerInstance.networkPlayer) {
            coin = playerInstance.coin;
            break;
        }
    }
    coin++;
    //Overwrite the data of other players with the new correct score
    networkView.RPC("UpdateMoney",RPCMode.All, Network.player, coin); 
}