Multiplayer only host can drive cars?

Okay so I don't use the original Unity 5 multiplayer network manager. I use my own network manager and it's perfectly fine, I've even played with my friend in Canada. I have a problem with my car script and only the person hosting the server can drive. If you are a host you can get in, drive around, get out, it's fine. But if you're a client when you get in the car all it does is play the sitting in car animation and disables your player X rotation and enabled the car cam rotation, but you never actually get in the car or drive it. I launched the Player game, hosted a server, and joined through the editor and it seems to be something to do with line 55 which is the disable player movement line.

Here's the error: NullReferenceException: Object reference not set to an instance of an object CarBehaviour.Update () (at Assets/Scripts/CarScripts/CarBehaviour.js:55)

And here's the code:

 #pragma strict
 
 static var inCar=false;
 private var inPrivateCar=false;
 static var isDriver=true;
 var driverSeat:GameObject;
 var passangerSeat:GameObject;
 var exitPos:GameObject;
 var mlHO:GameObject;
 var speed:float=5;
 var defSpeed:float;
 var topSpeed:float;
 var turnSpeed:float=180;
 var mlH:MouseLook;
 var ml:MouseLook;
 var carIdleSound:AudioClip;
 var carDrivingSound:AudioClip;
 private var useGrav=false;
 var isPlane=false;
 
 function Start () {
     defSpeed=speed;
     GetComponent.<NetworkView>().RPC("CarSounds", RPCMode.All);
 }
 
 function OnTriggerStay (col:Collider) {
     if(GetComponent.<NetworkView>().isMine) {
         if(col.tag=="Player") {
             if(Input.GetKeyUp(KeyCode.E)) {
                 yield WaitForSeconds(0.1);
                 inCar=true;
                 inPrivateCar=true;
                 ml.enabled=false;
             }
         }
     }
 }
 
 function Update () {
     if(GetComponent.<NetworkView>().isMine) {
             if(mlHO==null){mlHO=NetworkManagerScript.globalPlayer.FindWithTag("mlHO");}
             if(mlH==null){mlH=mlHO.GetComponent("MouseLook");}
             if(ml==null){ml=NetworkManagerScript.globalPlayer.GetComponent("MouseLook");}
         if(inCar==true) {
             mlH.enabled=true;
             ml.enabled=false;
         }
         else{
             mlH.enabled=false;
             ml.enabled=true;
             NetworkManagerScript.globalPlayer.transform.rotation.x=0;
             NetworkManagerScript.globalPlayer.transform.rotation.z=0;
         }
         if(inPrivateCar==true) {
             NetworkManagerScript.playerMovement.enabled=false;
             NetworkManagerScript.globalPlayer.GetComponent.<Rigidbody>().useGravity=false;
             NetworkManagerScript.globalPlayer.GetComponent.<Collider>().isTrigger=true;
             NetworkManagerScript.globalPlayer.GetComponent(AudioSource).enabled=false;
             mlH.enabled=true;
             ml.enabled=false;
             NetworkManagerScript.globalPlayer.transform.rotation=driverSeat.transform.rotation;
             if(isDriver==true) {
                 if(isPlane==true) {
                     transform.GetComponent.<Rigidbody>().useGravity=false;
                 }
                 var steer=Input.GetAxis("Horizontal");
                 var throttle=Input.GetAxis("Vertical");
                 NetworkManagerScript.globalPlayer.transform.position=driverSeat.transform.position;
                 NetworkManagerScript.globalPlayer.transform.parent=driverSeat.transform;
                 if(Input.GetKey(KeyCode.W)) {
                     //drive forward
                 } 
                 if (throttle!=0 || speed>=defSpeed) {
             if(!GetComponent.<AudioSource>().isPlaying) {
                     GetComponent.<NetworkView>().RPC("DrivingClip", RPCMode.All);
             }
                     if(speed<=topSpeed) {
                         speed+=0.1f;
                     }
                     if(speed>=topSpeed) {
                         speed=defSpeed;
                     }
                     var moveDist=throttle*speed*Time.deltaTime;
                     var turnAngle=steer * turnSpeed * Time.deltaTime * throttle;
                     transform.rotation.eulerAngles.y+=turnAngle;
                     transform.Translate(Vector3.right*moveDist);
             }
             else{
                 if(speed<=defSpeed) {
                     speed=defSpeed;
                 }
                 if(speed>=defSpeed) {
                     speed-=defSpeed;
                 }
             if(!GetComponent.<AudioSource>().isPlaying && throttle<=0) {
             GetComponent.<NetworkView>().RPC("IdleCLip", RPCMode.All);
             }
             }
             }
             else{
                 NetworkManagerScript.globalPlayer.transform.position=passangerSeat.transform.position;
                 NetworkManagerScript.globalPlayer.transform.parent=driverSeat.transform;
                 NetworkManagerScript.globalPlayer.transform.rotation=passangerSeat.transform.rotation;
             }
             if(Input.GetKeyDown(KeyCode.E)) {
                 NetworkManagerScript.globalPlayer.transform.position=exitPos.transform.position;
                 NetworkManagerScript.globalPlayer.transform.parent=null;
                 mlHO.transform.rotation.y=NetworkManagerScript.globalPlayer.transform.rotation.y;
                 inCar=false;
                 inPrivateCar=false;
             }
         }
         else{
             useGrav=true;
             if(useGrav==true)  {
                 NetworkManagerScript.globalPlayer.GetComponent.<Rigidbody>().useGravity=true;
                 useGrav=false;
             }
             NetworkManagerScript.playerMovement.enabled=true;
             NetworkManagerScript.globalPlayer.GetComponent.<Collider>().isTrigger=false;
             NetworkManagerScript.globalPlayer.GetComponent(AudioSource).enabled=true;
             mlHO.transform.rotation.y=NetworkManagerScript.globalPlayer.transform.rotation.y;
             if(!GetComponent.<AudioSource>().isPlaying) {
             GetComponent.<NetworkView>().RPC("NullClip", RPCMode.All);
             }
         }
     }
 }
 
 @RPC
 function CarSounds () {
     GetComponent.<AudioSource>().Play();
 }
 
 @RPC
 function IdleCLip () {
     GetComponent.<AudioSource>().clip=carIdleSound;
     GetComponent.<AudioSource>().Play();
 }
 
 @RPC
 function DrivingClip () {
     GetComponent.<AudioSource>().clip=carDrivingSound;
     GetComponent.<AudioSource>().Play();
 }
 
 @RPC
 function NullClip () {
     GetComponent.<AudioSource>().Stop();
 }
 
 function OnCollisionEnter (col:Collision) {
     if(col.gameObject.tag=="Col") {
         speed=0;
         yield;
         speed=defSpeed;
     }
 }

Thank you very much for your time and thanks in advance for help or attempt to help! :D