PHP - Change Active Directory Password

You are changing the password for  ". $info[$i]["givenname"][0] .", " . $info[$i]["sn"][0] ." (" . $info[$i]["samaccountname"][0] .") to " . $_POST['user_pass'] ."
\n";
             $passwd1 = $_POST['user_pass'];
              $userDn = $info[$i]["distinguishedname"][0];
              $newPassword = $passwd1;
      $newPassword = "\"" . $newPassword . "\"";
      $len = strlen($newPassword);
      for ($i = 0; $i < $len; $i++){
            $newPassw .= "{$newPassword{$i}}\000";}
      $newPassword = $newPassw;
      $userdata["unicodePwd"] = $newPassword;
      $result = ldap_mod_replace($ldap, $userDn , $userdata);
      if ($result) echo "Your password has been changed!" ;
      else echo "There was a problem changing your password, please call IT for help"; 
 }
         }
        @ldap_close($ldap);
?>