Description:
------------
When using LDAP to authenticate ActiveDirectory users hosted on Windows Server 2003 I get some issues connecting with all users.

Reproduce code:
---------------
global $ad_opts;

   $auth = ldap_connect($serverAddress)
   	or die("Could not connect to LDAP server.");

   # SET VERSION
   #################
   ldap_set_option($auth, LDAP_OPT_PROTOCOL_VERSION, 3);
   ldap_set_option($auth, LDAP_OPT_REFERRALS, 0);
   

   $login = ldap_bind($auth, $u, $p);

   if(!$login) {
      return 0;
   }

   return 1;

}

Expected result:
----------------
I expect the function to return 1 if the correct user credentials have been supplied.

Actual result:
--------------
While this works for most users, there have been a few users I've had trouble authenticating. Even though the username/password are correct, it fails. The strange thing is, users in the same 'directory' as the user are authenticated through LDAP. Also, this user has no trouble actually logging into the Windows network so I have no idea why this may be happening.