MS Access Database: your server is running with windows operating system, and it's using the window's database, named access.. The database is good for storing some personal data (as from what i heard, it's easy to use with a graphical user interface), other than that, it's not good for much else in my mind..
PHP 4.0pMyAdmin.. erm.. don't you mean php 4.0, phpMyAdmin?
php 4.0: it's a web specific language that helps you serve dynamic data.. such as those pulled from a database, it has a huge library and nice documentations.. very popular, almost all self-respecting hosts supports at least php 4.0
phpMyAdmin: build with php, and it's a frontend for MySQL databases.. you can browse and modify your whole database with the frontend, very useful