I’ve gotten this error to stop by adding this code to httpd.conf:
<Files *.php>
SetOutputFilter PHP
SetInputFilter PHP
LimitRequestBody 9524288
</Files>
AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps
It seems that the system comes configured for php but the apache install doesn’t put it into the default config file.
Also added index.php to the directoryindex list.