PHP time confusion

PHP (5.3.5) seems only wanting English date format:
Few days ago, I wanted to convert German month names (Februar, März etc.) into time and it failed. Although

$>locale -a | grep de_DE
de_DE
de_DE@euro
de_DE.utf8

says de_DE is installed. Strange. See here:

<?php 
//print_r(localeconv());  
setlocale(LC_ALL,"de_DE");  
setlocale(LC_TIME,"de_DE"); 
//print_r(localeconv());  
echo strtotime("01. October 2011")."\n";  
echo strtotime("01. Dezember 2011")."\n"; 
// echo strtotime("01. Dezember 2011")."\n"; 
// echo strftime("%d %B %Y","01 Dezember 2011");
echo "\n"; 
// echo strftime("%B","Dezember");echo "\n";  
//var_dump(date_parse("01 Dezember 2011")); ?>

What would you expect? That is what I'm get:

$>php test.php
1317420000

Right, German month names are not recognized anymore.