[PHP] Problem on OpenDir()

[Jack]

Dear all
I was trying to check if a directory exist in a specific folder, but i got this error 
message as below : 
Warning: OpenDir: Invalid argument (errno 22) in C:\InetPub\wwwroot\Nedcor Internal 
Live\Reports\Bills Reports\page.php on line 21

here is the code : 
<?
$handle=opendir("c:\\");
$dirname=$filepath.$folder;
if (is_dir("Aegis"))
 {
/*  while (($file=readdir($handle))!==false) 
  {
   if (ereg($premondate,$file))
   {
   copy($file, $filepath.$folder."/".$file);
   }

 closedir($handle);

  }
*/
 }

The strange thing is, the script had worked for once, but in the middle of test stage, 
there is a permission error to the folder and after i fixed it, it seems keep prompt 
me the Invalid Argument instead of open the folder.
Don't know what is going on! pls help!

Thx a lot,
Jack