Move() function doesn't work on character controller!

What's wrong with the Move() and SimpleMove() functions?

When I use them on a character controller they highlight in red and create an error log in the console.

Has this function been deprecated?

Here is my code...

 using UnityEngine;
 using System.Collections;
 
 public class CharacterController : MonoBehaviour {
 
     public float MoveSpeed;
     public float RotationSpeed;
 
     CharacterController cc;
 
     void Start()
     {
         cc = GetComponent <CharacterController> ();
     }
 
     void Update()
     {
         transform.Rotate (new Vector3(0, Input.GetAxis ("Horizontal") * RotationSpeed * Time.deltaTime, 0));
 
         Vector3 forward = Input.GetAxis ("Vertical") * transform.TransformDirection(Vector3.forward) * MoveSpeed;
         cc.Move (forward);
     }
 
 }