Spawning Clients

I make a multiplayer game with max 4 Players (1 Server + 3 Clients). I have four different spawn-positions. The Server takes the first spawn-position. The first Client shoult take the next spawn-position, the seceond client the next spawn-position, etc. With my code, all Clients spawn at the first postion. Why?

 [System.Serializable]
 public class SpawnPoint
 {
     SpawnPoint()
     {
         isAvailable = true;
     }
 
     public Transform transform;
     public GameObject playerPrefab;
     public bool isAvailable;
 }
 
 public class SpawnManager : MonoBehaviour
 {
     public SpawnPoint[] spawnPoint = new SpawnPoint[4];
 
     private int m_playerCount = 0;
 
     void OnServerInitialized()
     {
         Network.Instantiate(spawnPoint[0].playerPrefab, spawnPoint[0].transform.position, spawnPoint[0].transform.rotation, 0);
         spawnPoint[0].isAvailable = false;
     }
 
     void OnPlayerConnected(NetworkPlayer player)
     {
         networkView.RPC("PlayerCount", RPCMode.Others, Network.connections.Length);
     }
 
     void OnConnectedToServer()
     {
         SpawnPlayer(m_playerCount);
     }
 
     void SpawnPlayer(int index)
     {
         Network.Instantiate(spawnPoint[index].playerPrefab, spawnPoint[index].transform.position, spawnPoint[index].transform.rotation, 0);
     }
 
     [RPC]
     void PlayerCount(int value)
     {
         m_playerCount = value;
     }
 }