Please take a look at your addtype directives.
It looks to me like Apache is telling the browser that it's sending a document type of application/php for scripts with extensions like .php5. In fact Apache is supposed to tell the browser that the script is outputting text/html.
Please try this:
AddType text/html .php
Regarding the suggestion above that you should tell the browser that you are outputting a PHP script: It seemed like an unusual idea to me. I googled it and found that there is quite a bit of discussion about it on the web. Apparently there are cases where you might want to say that you are sending a PHP script (even though Apache is supposed to execute the script and emit text/html,) and there are also cases where the browser simply doesn't recognize that specific Mime Type.
Clearing your browser cache is always a good idea.
In case it's helpful here's a copy of my /etc/httpd/conf.d/php.conf file from a server running CentOS 5.9:
#
# PHP is an HTML-embedded scripting language which attempts to make it
# easy for developers to write dynamically generated webpages.
#
<IfModule prefork.c>
LoadModule php5_module modules/libphp5.so
</IfModule>
<IfModule worker.c>
LoadModule php5_module modules/libphp5-zts.so
</IfModule>
#
# Cause the PHP interpreter to handle files with a .php extension.
#
AddHandler php5-script .php
AddType text/html .php
#
# Add index.php to the list of files that will be served as directory
# indexes.
#
DirectoryIndex index.php
#
# Uncomment the following line to allow PHP to pretty-print .phps
# files as PHP source code:
#
#AddType application/x-httpd-php-source .phps