Hi Jack_mcs,
thanks for your answer.
I replaced the following files from my backup now:
root/shop/.htaccess
root/shop/includes/application_top.php
root/shop/functions/html_output.php
And now, the order process works fine.
The webshop located in the subfolder 'shop'. In the .htaccess file the path is 'RewriteBase /shop/'.
In the /includes/configure.php I wrote the following pathes:
define('HTTP_SERVER', 'http://www.anyurl.de'); // eg, http://localhost - should not be empty for productive servers
define('HTTPS_SERVER', 'https://ssl-account.com/anyurl.de'); // eg, https://localhost - should not be empty for productive servers
ssl-account.com is the SSL-Proxy from Hoster.
Could this be the problem?
Thanks, atom11