input.getaxis not working

hi, I've got a car script that I've made from this tutorial : link text

but the input.getaxis does not seem to work and the car doesn't move unless i put in values manually into the editor

heres my script :

 //variables
 private var accel : Vector3;
 public var throttle : float;
 private var deadZone = 0.001 ;
 private var myRight : Vector3;
 private var velo : Vector3;
 private var flatVelo : Vector3;
 private var relativeVelocity : Vector3;
 private var dir : Vector3;
 private var flatDir : Vector3;
 private var carUp : Vector3;
 private var carTransform : Transform;
 private var carRigidbody : Rigidbody;
 private var engineForce : Vector3;
 
 private var turnVec : Vector3;
 private var imp : Vector3;
 private var rev : float;
 private var actualTurn : float;
 private var carMass : float;
 private var wheelTransform : Transform[] = new Transform[4];
 public var actualGrip : float;
 public var horizontal : float;
 private var maxSpeedToTurn : float = .2;
 
 //cars wheels
 public var frontLeftWheel : Transform;
 public var frontRightWheel : Transform;
 public var rearLeftWheel : Transform;
 public var rearRightWheel : Transform;
 
 //transforms for steering
 public var LFWheelTransform : Transform;
 public var RFWheelTransform : Transform;
 
 //car physics
 public var power : float = 300;
 public var maxSpeed : float = 50;
 public var carGrip : float = 70;
 public var turnSpeed : float = 3.0;
 
 private var slideSpeed : float;
 public var mySpeed : float;
 
 private var carRight : Vector3;
 private var carFwd : Vector3;
 private var tempVEC : Vector3;
 
 function Start()
     {
     carTransform = transform;
     carRigidbody = rigidbody;
     carUp = carTransform.up;
     carMass = rigidbody.mass;
     carFwd = Vector3.forward;
     carRight = Vector3.right;
     setUpWheels();
     carRigidbody.centerOfMass = Vector3(0,-0.7,0.35);
     }
     
 function Update()
     {
     carPhysicsUpdate();
     checkInput();
     }
 
 function LateUpdate()
     {
     rotateVisualWheels();
     engineSound();
     }
     
 function setUpWheels()
     {
     if((null == frontLeftWheel || null == frontRightWheel || null == rearLeftWheel || null == rearRightWheel))
         {
         Debug.Log("wheel transforms not plugged in");
         //Debug.break;
         }
     else
         {
         wheelTransform[0] = frontLeftWheel;
         wheelTransform[1] = frontRightWheel;            
         wheelTransform[2] = rearLeftWheel;
         wheelTransform[3] = rearRightWheel;
         }
     }
 
 private var rotationAmount : Vector3;
                 
 function rotateVisualWheels()
     {
     LFWheelTransform.localEulerAngles.y = horizontal * 30;
     RFWheelTransform.localEulerAngles.y = horizontal * 30;
     
     rotationAmount = carRight * (relativeVelocity.z*1.6*Time.deltaTime*Mathf.Rad2Deg);
     
     wheelTransform[0].Rotate(rotationAmount);
     wheelTransform[1].Rotate(rotationAmount);
     wheelTransform[2].Rotate(rotationAmount);
     wheelTransform[3].Rotate(rotationAmount);
     }
 
 private var deviceAccelerometerSensitivity : float = 2;
 
 function checkInput()
     {
     if ((Application.platform == RuntimePlatform.IPhonePlayer) || (Application.platform == RuntimePlatform.Android))
         {
         accel = Input.acceleration * deviceAccelerometerSensitivity;
         
         if(accel.x > deadZone || accel.x < -deadZone)
             {
             horizontal = accel.x;
             }
         else
             {
             horizontal = 0;
             }
         throttle = 0;
         
         for (var touch : Touch in Input.touches)
             {
             if(touch.position.x > Screen.width - Screen.width/3 && touch.position.y < Screen.height / 3)
                 {
                 throttle = 1;
                 }
             else if (touch.position.x <Screen.width/3 && touch.position.y < Screen.height / 3)
                 {
                 throttle = -1;
                 }
             }
         }
     
     else if((Application.platform == RuntimePlatform.WindowsEditor) || (Application.platform == RuntimePlatform.WindowsWebPlayer))
         {
         horizontal = Input.GetAxis("Horizontal");
         throttle = Input.GetAxis("Vertical");
         }
     }
 
 function carPhysicsUpdate()
     {
     myRight = carTransform.right;
     velo = carRigidbody.velocity;
     tempVEC = Vector3(velo.x,0,velo.z);
     flatVelo = tempVEC;
     dir = transform.TransformDirection(carFwd);
     tempVEC = Vector3(dir.x,0,dir.z);
     flatDir = Vector3.Normalize(tempVEC);
     relativeVelocity = carTransform.InverseTransformDirection(flatVelo);
     slideSpeed = Vector3.Dot(myRight, flatVelo);
     mySpeed = flatVelo.magnitude;
     rev = Mathf.Sign(Vector3.Dot(flatVelo,flatDir));
     engineForce = (flatDir * (power * throttle) * carMass);
     actualTurn = horizontal;
     
     if (rev<0.1f)
         {
         actualTurn=-actualTurn;
         }
     
     turnVec = (((carUp * turnSpeed) * actualTurn) * carMass) * 800;
     
     actualGrip = Mathf.Lerp(100, carGrip, mySpeed *0.02);
     imp = myRight*(-slideSpeed * carMass * actualGrip);
     }
     
 function slowVelocity()
     {
     carRigidbody.AddForce(-flatVelo * 0.8);
     }
 
 function engineSound()
     {
     audio.pitch = 0.30 + mySpeed * 0.025;
     
     if(mySpeed>30)
         {
         audio.pitch = 0.25 + mySpeed * 0.015;
         }
     if(mySpeed>40)
         {
         audio.pitch = 0.20 + mySpeed * 0.013;
         }
     if(mySpeed>50)
         {
         audio.pitch = 0.15 + mySpeed * 0.011;
         }
     
     if(audio.pitch>2.0)
         {
         audio.pitch = 2.0;
         }
     }
 
 function FixedUpdate()
     {
     if(mySpeed < maxSpeed)
         {
         carRigidbody.AddForce(engineForce*Time.fixedDeltaTime);
         }
     if(mySpeed > maxSpeedToTurn)
         {
         carRigidbody.AddTorque(turnVec*Time.fixedDeltaTime);
         }
     else if(mySpeed < maxSpeedToTurn)
         {
         return;
         }
     carRigidbody.AddForce(imp * Time.fixedDeltaTime);
     }
 

please help...