Since 4.3.2RC the default Apache 2 sapi is the apache2handler and is no longer filter based. Therefor you should use
AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps
If you do want to use the old filter sapi, you need to use
So the simple fix for this is to open up your httpd.conf and look for the lines containing SetOutputFilter or SetInputFilter. Comment these lines out, save the file and restart Apache.
This will prevent your error logs from bloating with the unknown filter error.