Network Game not working.

When I test my networked game in Unity, everything works fine. However when I build it, I get nothing but a blank screen. Anyone know whats wrong?

Here’s my script:
var playerPrefab:GameObject;
var spawnObject:Transform;
var gameName:String = “Yung_Pharaoh_Test_Network”;

private var refreshing:boolean;
private var hostData:HostData[];

private var btnX:float;
private var btnY:float;
private var btnW:float;
private var btnH:float;

function Start(){
	btnX = Screen.width * 0.05;
	btnY = Screen.width * 0.05;
	btnW = Screen.width * 0.1;
	btnH = Screen.width * 0.1;
}

function startServer(){
	Network.InitializeServer(32, 25001, !Network.HavePublicAddress);
	MasterServer.RegisterHost(gameName,"Network Test","This is a test");	
}

function refreshHostList(){
	MasterServer.RequestHostList(gameName);
	refreshing = true;
}

function Update(){
	if(refreshing){
		if(MasterServer.PollHostList().Length > 0){
			refreshing = false;
			Debug.Log(MasterServer.PollHostList().Length);
			hostData = MasterServer.PollHostList();
		}
	}
}


function spawnPlayer(){
	Network.Instantiate(playerPrefab, spawnObject.position, Quaternion.identity, 0);
}

//Messages
function OnServerInitialized(){
	Debug.Log("Server Initialized");
	spawnPlayer();
}

function OnConnectedToServer(){
	spawnPlayer();
}

function OnMasterServerEvent(mse:MasterServerEvent){
	if(mse == MasterServerEvent.RegistrationSucceeded){
		Debug.Log("Registered Server");
	}
}

//GUI			
function OnGUI(){
	if(!Network.isClient && !Network.isServer){
		if(GUI.Button(Rect(btnX, btnY, btnW, btnH), "ST4RT_S3RV3R")){
			Debug.Log("Starting Server");
			startServer();
		}
		
		if(GUI.Button(Rect(btnX, btnY * 1.2 + btnH, btnW, btnH), "R3FR3SH_HØSTS")){
			Debug.Log("Refreshing");
			refreshHostList();
		}
		if (hostData){
			for(var i:int = 0; i < hostData.length; i++){
				if(GUI.Button(Rect(btnX * 1.5 + btnW, btnY * 1.2 +(btnH * i), btnW * 3, btnH * 0.5), hostData*.gameName)){*

_ Network.Connect(hostData*);_
_
}_
_
}_
_
}_
_
}_
_
}*_

Replace this condition :

if(!Network.isClient && !Network.isServer){
}

by below:

if (Network.peerType == NetworkPeerType.Disconnected && !Network.isServer){
}

Hoping it will work.