directory issue

I cant seem to find the problem...
currently the script im running is supposed to display the main directories , and when you click it it should display the subdirectories.

whats happening is that its listing all the directories on the same page... here is the php file.
Thanks!

<?php

$cdir = dirname(__FILE__); 
$DirectoriesToScan = array(realpath($cdir));
$DirectoriesScanned = array();
while (count($DirectoriesToScan) > 0) {
foreach ($DirectoriesToScan as $DirectoryKey => $startingdir) {
if ($dir = @opendir($startingdir)) {
while (($file = readdir($dir)) !== false) {
if (($file != '.') && ($file != '..') && ($file != 'files')) {
$RealPathName = realpath($startingdir.'/'.$file);
if (is_dir($RealPathName)) {
if (!in_array($RealPathName, $DirectoriesScanned) && !in_array($RealPathName, $DirectoriesToScan)) {
$DirectoriesToScan[] = $RealPathName;
$DirList[] = $RealPathName;
}
} 
}
}
closedir($dir);
}
$DirectoriesScanned[] = $startingdir;
unset($DirectoriesToScan[$DirectoryKey]);
}
}
$DirList = array_unique($DirList); 
sort($DirList); 
echo "<br><table align=center width=100%>\n"; 
$columns=3; 
$i = 0; 
foreach ($DirList as $dirname) { 
if ($i == $columns) 
{ 
echo "</tr><tr>"; 
$i = 0; 
} 
elseif ($i == 0) 
{ 
echo "<tr>"; 
} 

$i++; 

$dirnames = str_replace("$cdir/","",$dirname); 
$back_root = dirname(__FILE__) . '/..'; 
$back_root = str_replace("/..","",$back_root); 
$back_root = str_replace("$cdir/","",$back_root); 
$back_root = str_replace("$root/m/","",$back_root);


$dirnames = str_replace(" ","_",$dirnames); 
$count = count($DirList); 
if (strpos($dirnames,"/")){
$list_name = explode("/",$dirnames);
echo "<td>&nbsp;&nbsp;&nbsp;&nbsp;<span style=\"text-transform: uppercase\"><a href=\"?page=filter&location=$dirnames&section=$back_root\">$list_name[1]</font></a>&nbsp;&nbsp;&nbsp;</td>\n"; 
}else{
echo "<td>&nbsp;&nbsp;&nbsp;&nbsp;<span style=\"text-transform: uppercase\"><a href=\"?page=filter&location=$dirnames&section=$back_root\">$dirnames</font></a>&nbsp;&nbsp;&nbsp;</td>\n"; 
}  
}
for ($x=$i; $x<$columns ; $x++) 
echo "<td></td>"; 
echo "</tr></table>\n"; 
?> 

PHP: