[Solved] AutoType script doesn´t work!

(Maybe my English isn´t perfect) Hi, I want to use this script, but with the JS version I get an error and the CS version does nothing.

The error: "ToCharArray" is not a member of "Object"

 var letterPause = 0.2;
 var sound : AudioClip;
  
 private var word;
  
 function Start () {
     word = guiText.text;
     guiText.text = "";
     TypeText ();
 }
  
 function TypeText () {
     for (var letter in word.ToCharArray()) {
         guiText.text += letter;
         if (sound)
             audio.PlayOneShot (sound);
         yield WaitForSeconds (letterPause);
     }        
 }

And the CS version does nothing, the text will be displayed normally (Not letter by letter)

CS:

 using UnityEngine;
 using System.Collections;
  
 public class AutoType : MonoBehaviour {
  
     public float letterPause = 0.2f;
     public AudioClip sound;
  
     string message;
  
     // Use this for initialization
     void Start () {
         message = guiText.text;
         guiText.text = "";
         StartCoroutine(TypeText ());
     }
  
     IEnumerator TypeText () {
         foreach (char letter in message.ToCharArray()) {
             guiText.text += letter;
             if (sound)
                 audio.PlayOneShot (sound);
                 yield return 0;
             yield return new WaitForSeconds (letterPause);
         }      
     }
 }

Thanks in advance...