You probably have not loaded the apache2mod_php, or apache2mod_mysql, got to install software and find the application
install and restart apache with
Ensure the mysql server is started by checking for mysql
check the module is working with making a text file
<? phpinfo() ?>
put it into your website in /var/www/html as test.php then
with your browser type
This will tell you if the mysql is loaded in apache and the location of all the files etc for mysql.