Only what I read in the manual: take the trailing slash off your dir, and add the addtype directive
# For PHP 5 do something like this:
LoadModule php5_module "c:/php/php5apache2.dll"
AddType application/x-httpd-php .php
# configure the path to php.ini
"C:/Program Files/PHP"
I do know (remember now, it's been years) you need the addtype directive in httpd.conf to tell apache to handle any new file extention like .php .dhtml etc