Network how to send data/activate function

I'm just beginning to learn networking, ...

I did read all the unity reference:

http://docs.unity3d.com/Documentation/Components/NetworkReferenceGuide.html

and I couldn't figure out a thing how to even start, ...

than I followed this on youtube till step 4

but I want it to work separatly (server script and client script)

and I get an error, but I can connect to server ok.

 MissingComponentException: There is no 'NetworkView' attached to the "_Networking" game object, but a script is trying to access it.
 You probably need to add a NetworkView to the game object "_Networking". Or your script needs to check if the component is attached before using it.

I have server/client attached to empty GO _Networking,

for server I disable client script and build & run it.

for client I activate client and disable server script and run it under unity it self, but change color button produces me an error.

where am I going wrong?

both scripts:

Server

 using UnityEngine;
 using System.Collections;
 
 public class Server : MonoBehaviour {
     public GameObject Planet;
     public string IP = "127.0.0.1";
     public int Port = 25001;
     void OnGUI (){
         
         if (Network.peerType == NetworkPeerType.Disconnected){
             if (GUILayout.Button("Start Server")){
                 Network.InitializeServer(10, Port);
             }
         }
         else {
             if (Network.peerType == NetworkPeerType.Server){
                 GUILayout.Label("Server");
                 GUILayout.Label("Connections: " + Network.connections.Length);
                 if (GUILayout.Button("Logout")){
                     Network.Disconnect(5);
                 }
             }
         }
     }
     [RPC]
     void ChangeColor (){
         Planet.renderer.material.color = Color.green;
     }
 }

Client

 using UnityEngine;
 using System.Collections;
 
 public class Client : MonoBehaviour {
     public GameObject Planet;
     public string IP = "127.0.0.1";
     public int Port = 25001;
     void OnGUI (){
         
         if (Network.peerType == NetworkPeerType.Disconnected){
             if (GUILayout.Button("Start Client")){
                 Network.Connect(IP,Port);
             }
         }
         else {
             if (Network.peerType == NetworkPeerType.Client){
                 GUILayout.Label("Client");
                 if (GUILayout.Button("Change collor")){
                     networkView.RPC("ChangeColor", RPCMode.All);
                 }
                 if (GUILayout.Button("Logout")){
                     Network.Disconnect(5);
                 }
             }
         }
     }
     [RPC]
     void ChangeColor (){
         Planet.renderer.material.color = Color.green;
     }
 }

thanks in advance just a gently push in right direction will be nice, ...