I have done a fresh install of wordpress, works fine. Have then followed instructions to use german language mo file.
I get the following errors in php log and their is no response sent to the browser other than a 200 http header.
Removing the .mo file fixes the problem. The .mo file is fine as I have done an install on the dev environment using the exact same file (verified using diff) and it works fine.
This occurs on a debian machine and on a redhat advanced server machine with the exact same symptoms. Versions of other things are:
php - 5.1.4
apache - 2.0.58
mysql - 4.1.20-standard
PHP Warning: unpack() [function.unpack]: Type V: not enough input, need 4, have 0 in /home/sites/wordpress-de/wordpress/wp-includes/gettext.php on line 85