Description:
------------
using server 2003 with iis6
a file_exists used on a tree of directory reports:

file_exists("c:") = true
file_exists("c:/new") = false
file_exists("c:/new/new") = true

second call is wrong.

it happens with all first directories on a drive root

Reproduce code:
---------------
<?
            mkdir("d:/new",0777);
            mkdir("d:/new/new",0777);
            $dir = "d:/new/new";
            $dir_parts = preg_split('!/+!', $dir, -1, PREG_SPLIT_NO_EMPTY);
            $new_dir = ($dir{0} == '/') ? '/' : '';
            foreach ($dir_parts as $dir_part) {
                $new_dir .= $dir_part;
                if(file_exists($new_dir)) {
                  echo "$new_dir exists\n";
                }
                else {
                  echo "$new_dir doesn't exists\n";
                }
                $new_dir .= '/';
            }
?>

Expected result:
----------------
d: exists
d:/new exists 
d:/new/new exists 

Actual result:
--------------
d: exists
d:/new doesn't exists
d:/new/new exists