Cant use .NET classes

Im trying to make a file explorer based on some scripts i got in unity forums but im getting the following error in my script.

BCE0019: 'GetFiles' is not a member of 'System.IO.DirectoryInfo'.

My Script:

 #pragma strict
 
 import System.Collections.Generic;
 import System.IO;
 
 var path : String = "./";
 var fileTypes : String[] = ["ogg", "wav"];
 
 var files : FileInfo[];
 var Source : AudioSource;
 var audioclips : List.<AudioClip> = new List.<AudioClip>();
 
 function Start () {
  if(Application.isEditor) {
      path = "Assets/";
      }
 }
 
 function Update () {
 
 }
 
 function ObtenerDatosDir() {
     var info : System.IO.DirectoryInfo = new System.IO.DirectoryInfo(path);
     files = info.GetFiles();
 }

Any idea why i cant make it work?