Get a list of file names from directory using URLLoader and php

I hope this is the right place for this post. I am trying to trace a list of all file names in a directory using php. Unfortunately i don’t know how to use php and am trying to modify a code i found on the internet. any help would be appreciated.

My php code looks like this:

   $dir = 'CastingSoundFiles/MissA';

   $dirHandle = opendir($dir);
   $count = -1;
   $returnstr = "";
   while ($file = readdir($dirHandle)) { 
      if(!is_dir($file) && strpos($file, '.mp3')>0) {
         $returnstr .= '&f'.$count.'='.$file;
   $returnstr .= '&';
   echo $returnstr;

and I’m loading it in flash like this:

    public class GetFiles
        var loader:URLLoader = new URLLoader();
        public function GetFiles()
            loader.addEventListener(Event.COMPLETE, useData);
            loader.load(new URLRequest("readfromdir.php"));
        function useData(event:Event):void {
            var data:String =;

this just traces the php file. how do i run this php code to get the returnstr variable.

Thanks for help sorry im so confused.