THe portal or content management system as they are often referred as require a database to store the content of the system. Your host needs to offer to you a database of some type thats supported by your portal sytem. The most common database thats offered is mysql.
If your account does not have database support then to use a system like this you will need to upgrade your account to one that does support a database.
The directions are expecting you to have already setup a database with your hosting control panel. How do you do that? Well it will depend on your host but here is a list of some tutorals and one of them is how to create a database with the common cpanel hosting system. http://www.v7inc.com/support.php
Look down at the MySQL Databases section. Once you have created the DB and the DB user and assigned the user to the DB you will need to edit a config file or enter in the installer the database name, username and password for that database so the script can connect to the database.