Why doesn't this server work online?

Hi everybody

I wrote this script for my server and it works fine on my own computer when I have 2 instances of it open, 1 for the server and 1 for the client. But it doesn't work online? How can I make this script work online?

 var gameName : String = "Arandomgamename";
 private var refreshing : boolean;
 var hostData : HostData[];
 var player : GameObject;
 private var btnX : float;
 private var btnY : float;
 private var btnW : float;
 private var btnH : float;
 var myCam : Camera;
 var myAudioListener : AudioListener;
 var useNat : boolean = true;
 
 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,useNat);
 MasterServer.RegisterHost(gameName, "Random Name", "Derp");
 }
 
 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 () {
 var playerInstance : GameObject = Network.Instantiate(player, gameObject.transform.position, gameObject.transform.rotation, 0);
 myCam = playerInstance.GetComponentInChildren(Camera);
 myAudioListener = playerInstance.GetComponentInChildren(AudioListener);
 if (playerInstance.networkView.isMine){
 if (myCam.enabled == false){
 myCam.enabled = true;
 }
 if (myAudioListener.enabled == false){
 myAudioListener.enabled = true;
 }
 }
 }
 
 // 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), "Start Server")){
 Debug.Log("Server Starting");
 StartServer ();
 }
 if (GUI.Button(Rect(btnX, btnY * 1.2 + btnH, btnW, btnH), "Refresh Hosts")){
 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[i].gameName)){
 Network.Connect(hostData[i].guid);
 Debug.Log("herp");
 }
 }
 }
 }
 }