Typo3 404 in chosen language

AdditionalConfiguration.php

<?php

function logger($value)
{
  $output = "\n" . print_r($value, TRUE) . "\n";
  file_put_contents('php://stderr', $output);
  //observe in apache log (tail -f /var/log/apache2/error.log)

}
 // http://wiki.sklein-medien.de/doku.php?id=typo3:404
if (!defined('TYPO3_MODE')) {die('Access denied.');}
$GLOBALS ['TYPO3_CONF_VARS']['FE']['debug'] = true;

$languages = $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['lang']['availableLanguages'];
$uri = $_SERVER['REQUEST_URI'];
logger($uri);

foreach ($languages as $l) {
  $l = ($l == 'da') ? 'dk' : $l; //fix danish /da/
  $pattern =  '/\/' . $l . '\//';
  if (preg_match($pattern, $uri)) {
    $GLOBALS['TYPO3_CONF_VARS']['FE']['pageNotFound_handling'] = ''.$l.'/404/';
  }
}
logger($GLOBALS['TYPO3_CONF_VARS']['FE']['pageNotFound_handling']);