Do you have php (4 or 5) apache2 mod installed?
Do you have
Code:
<IfModule mod_php5.c>
AddType application/x-httpd-php .php .phtml .php3
AddType application/x-httpd-php-source .phps
</IfModule>
on your /etc/apache2/mods-enabled/php5.conf file (or version equivalent file)?
Do you have
Code:
LoadModule php5_module /usr/lib/apache2/modules/libphp5.so
on your /etc/apache2/mods-enabled/php5.load file?
Do you think you need some php special options on your VirtualHosts declarations?
May be you can post your log(s) file(s) if they have some interesting info on module loading or on php execution process.