German First and Last Name

The code works, if it is not working then you haven't implemented it properly.

I used the code example exactly as it was found here:

http://www.gravityhelp.com/documentation/page/Gform_name_first

and here:

http://www.gravityhelp.com/documentation/page/Gform_name_last

I copied both code examples exactly as they were and placed them in my themes functions.php like so:

http://i.imgur.com/qgtr9.png

When I view my form, this is what I see:

http://i.imgur.com/MJwFU.png

So the code does work, but you need to make sure you have implemented it properly. It would go in your themes functions.php file.