apache2 and php4: apache does not execute php script

[Hannes Mayer <debiandude@gmail.com>]

Hi all!

I just installed apache2 (2.0.53-5) and php4 (4.3.10-8) (apt-get from
testing) on a sarge machine.
apache2 works, serving normal html pages, but it only serves php pages
as source code (download "save as" appears in browser).

I've uncommented the following lines in apache2.conf:
AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps

Furthermore there are no error messages in error.log.
php4.conf and php4.load were added automatically in mods-available and
the symlinks in mods-enabled are there.

I've googled a lot, but can't find a solution.
I'm very glad for any hints and pointers what I'm missing.

Thanks & best regards,
Hannes.