Getting "There is no NetworkIdentity on this object" but there is one attached.

I was following the tutorial here:

and I followed pretty much exactly as is, but I get a no NetworkIdentity on this object, NullReferenceException. The game runs fine but this error shows up in the console. I searched online and there was one thread but he had an issue with the object being a child of another.

I have a car, with a NetworkIdentity and NetworkTransform attached, registered in the NetworkManager as the Player prefab, with a script that uses isLocalPlayer attached.

Code (CSharp):

1. public class SetupLocalPlayer : NetworkBehaviour {
2.  
3.     [SyncVar]
4.     public string pname = "Player Name";
5.     // Use this for initialization
6.     void Start () {
7.         if (isLocalPlayer) {
8.             this.GetComponent<Driving> ().enabled = true;
9.             this.GetComponentInChildren<TextMesh> ().color = new Color (0, 221, 255);
10.         } else {
11.             this.GetComponentInChildren<TextMesh> ().color = new Color (255, 0, 0);
12.             Destroy(GetComponentInChildren<Camera>());
13.             Destroy(GetComponentInChildren<AudioListener>());
14.         }
15.     }
16.  
17.     void Update () {
18.         this.GetComponentInChildren<TextMesh> ().text = pname;
19.     }
20.  
21.  
22.     [Command]
23.     public void CmdChangeName(string newName){
24.         pname = newName;
25.     }
26. }

There was initially an old GUI script also, but that caused looots of lag, so I removed it from the sample. I tried another project with multiplayer networking and it threw weird unexplainable issues too. Overall Unity Multiplayer has been a huge pain. I'm relatively a newbie, so if anyone could explain what's going on, I'd really appreciate that!

I also cannot understand how to access UI element properties from the player object to retrieve player name from a text InputField I have. If someone could explain that too, that'd be great! (I know that's not part of this forum, but it's related to the same script.)