Compression help

I have wordpress running a 1&1 server. To add compression to my to site I added :

AddType x-mapp-php5 .php .shtml .html .htm .txt .js .css to my htaccess.

Then I added the following into a php.ini file:

output_handler=ob_gzhandler
auto_prepend_file=/kunden/homepages/27/d292845089/htdocs/PelicanFly/headers.php

I then created a file called header.php with this included:

<?
$pathinfo=pathinfo($_ENV['SCRIPT_FILENAME']);
$extension=$pathinfo['extension'];
$offset = 60 * 60 * 24 * 30;
if($extension=='css'){
header('Content-type: text/css; charset=utf-8');
header("Expires: ".gmdate("D, d M Y H:i:s", time() + $offset)." GMT");
header("Vary: Accept-Encoding");
}
if($extension=='js'){
header('Content-type: text/javascript; charset=utf-8');
header("Expires: ".gmdate("D, d M Y H:i:s", time() + $offset)." GMT");
header("Vary: Accept-Encoding");
}
?>

This compressed everything fine but it breaks my wordpress admin. It basically looks like the styles are broken.

If i remove .css from
AddType x-mapp-php5 .php .shtml .html .htm .txt .js .css

so:

AddType x-mapp-php5 .php .shtml .html .htm .txt .js .

It works fine because it is not compressing the css. I found a half solution to add:

define('WP_DEBUG', true);

to my wp-config file which fixes the syles but ofcourseshows all the debug logs in my wordpress admin. Can anyone help? I’m getting short on hair.

Muchos gracias.