Problem with player movements

Hi to everybody and thanks for your help.

I'm creating a 2D scroll game with deepness, ie, the player can moves to left-right and back-fron.

And the question is the next one:

I have modified the script of the official website (http://docs.unity3d.com/Documentation/ScriptReference/CharacterController.Move.html) like this:

 using UnityEngine;
 using System.Collections;
 
 public class MovimientoJugador : MonoBehaviour {
     public float speed = 6.0F;
     public float jumpSpeed = 8.0F;
     public float gravity = 20.0F;
     private Vector3 moveDirection = Vector3.zero;
     void Update() {
         CharacterController controller = GetComponent<CharacterController>();
         if (controller.isGrounded) {
             **moveDirection = new Vector3(Input.GetAxis("Horizontal"), Input.GetAxis("Vertical"), 0);**
             moveDirection = transform.TransformDirection(moveDirection);
             moveDirection *= speed;
         if (Input.GetButton("Jump"))
             moveDirection.y = jumpSpeed;
             
         }
         moveDirection.y -= gravity * Time.deltaTime;
         controller.Move(moveDirection * Time.deltaTime);
     }
 }

And the problem is that the player only moves to front, back and left, not right. What can be the reason and what can i do to solve them?

Other thing that i think can be the reason is the input config, but it looks like its good.

If anybody knows other script to do it, please tell me.

Thank you!!!

Regards, Dani.