Networking: Object is instantiated twice instead of once

Hi! In my networking game, two players (from one prefab) are spawned at two specific points (SpawnPoint 1 and 2) when the server is initialized and a client is connected. Both players are able to hit the GUI-Button "Start" and create a ball to play with. The ball is created randomly from a list of three sphere-prefabs. The ball-script attached to the three sphere-prefabs should do the following: destroy the sphere-clone when it passes behind a player and create a new ball, so the game continues automatically. I am having the following problems: 1. Instead of only one clone two clones are spawned when the sphere-object is destroyed, e.g. the clones multiply themself over time 2. I specified that the Server-Player is spawned at SpawnPoint 1 and the Client-Player at SpawnPoint 2. But when the Client connects the Server-Player is swaped from SpawnPoint 1 to SpawnPoint 2

I am very confused why these two things happend and have the feeling that they are connected. Any help woul be highly appreciated!

I attach the following codes

Srcipt (ConnectionGUI.js) for setting up the network game, including the instantiat-functions:

 //Variables for spawing prefabs
 var playerPrefab : GameObject;
 
 var sphereRange : GameObject[];
 
 var spawnpoint1 : Transform;
 var spawnpoint2 : Transform;
 
 //Variables for GUI
 var textures : Texture[];
 
 function OnGUI(){
     if(Network.peerType == NetworkPeerType.Disconnected){
     
         if (GUI.Button (new Rect(10,90,100,30), "Connect")){
             Debug.Log("button pressed");
             Debug.Log(remoteIP + " " + remotePort);
             Network.useNat = useNAT;
             Network.Connect(remoteIP, remotePort);
             
         }
         //start server
         if (GUI.Button (new Rect(10,130,100,30), "Start Server")){
             Network.useNat = useNAT;
             Network.InitializeServer(32, listenPort);
         
         }
         
         remoteIP = GUI.TextField(new Rect(120,90,100,20),remoteIP);
         remotePort = parseInt(GUI.TextField(new Rect(230,90,40,20), remotePort.ToString()));
         
     }
     
     else{
         ipaddress = Network.player.ipAddress;
         port = Network.player.port.ToString();
         
         GUI.Label(new Rect(140,100,250,40), "IP Address: " + ipaddress + ":" + port);
         
         if (GUI.Button (new Rect(10,90,100,30), "Disconnect")){
             Network.Disconnect(200);
         }
         
         if (GUI.Button (new Rect(870, 90, 50, 50), "play")){
             for (var go : GameObject in FindObjectsOfType(GameObject))
                 go.SendMessage("spawnSphere", SendMessageOptions.DontRequireReceiver);
             
         }
     }
 }
 
 function spawnSphere(){
         var mySphere : GameObject = sphereRange[Random.Range(0, sphereRange.length)];
         Network.Instantiate(mySphere, mySphere.transform.position, mySphere.transform.rotation, 0);
 }
 
 
 //function on Client when Client is connected to server
 function OnConnectedToServer(){
     Debug.Log("Client connected");
     Network.Instantiate(playerPrefab, spawnpoint2.transform.position, spawnpoint2.transform.rotation, 0);
 }
 
 //function when Server is initalized
 function OnServerInitialized(){
     Debug.Log("Server initialized");
     Network.Instantiate(playerPrefab, spawnpoint1.transform.position, spawnpoint1.transform.rotation, 0);

Script (BallCont.js) attached to all sphere-prefabs (moving, adding to score, destroy and calling the instantiate function for creating a new sphere)

 #pragma strict
 
 var cSpeedC:float = 10.0;
 var sFactorC:float = 10.0;
 
 function Start () {
 
     rigidbody.AddForce(0,0,Random.Range(-5.0,5.0));
 }
 
 function Update () {
 
     //smoothing of ball movement
     var cvelC = rigidbody.velocity;
     var tvelC = cvelC.normalized * cSpeedC;
     rigidbody.velocity = Vector3.Lerp(cvelC, tvelC, Time.deltaTime * sFactorC);
     
     //check the right bounds (goal for player 1), add score and destroy
     if(transform.position.z > 8){
     
         var p1C = GameObject.Find("MainGameObject");
         p1C.GetComponent(PointsGUI).scPlayer1++;
         
         print("Player 1 spawn");
         
         var IntA = GameObject.Find("Camera");
         IntA.GetComponent(ConnectionGUI).spawnSphere();
         
         
         Destroy (gameObject);
         
     }
     
     //check the left bounds (goal for player 2), add score and destroy
     if(transform.position.z < -5){
     
         var p2C = GameObject.Find("MainGameObject");
         p2C.GetComponent(PointsGUI).scPlayer2++;
         
         print("Player 2 spawn");
         
     var IntB = GameObject.Find("Camera");
         IntB.GetComponent(ConnectionGUI).spawnSphere();
         
         Destroy (gameObject);
     }
 }

Sofar I tested the game only in local host and on one computer (two instances).