Did you run VuFind’s install.bat script? This should automatically create a database for you and load the appropriate tables. Then you just need to edit config.ini to make sure the connection string includes the appropriate username, password and database name. If the install script isn’t working for some reason, it might mean that XAMPP is putting files in different places from where the script expects them. In that case, you can manually create a database like you did, but you also have to make sure that you load the tables from the mysql.sql file under VuFind.
It is also important to understand that the database connection string does not relate directly to PHPMyAdmin or any file or web-based URL. The connection string should look like this:
username and password are login credentials that allow access to the database – the install.bat script will help you set up credentials that are only allowed to access the vufind database, which is the most secure approach. database_name is the name of the database you created. None of this maps directly to SQL files or paths on your hard drive… so the “root@localhost/xampp/phpmyadmin/publicatie.sql” path you have in your file will not work, as it contains some extra information that VuFind will not understand.
I apologize if this is somewhat confusing. If the information I have provided so far is not helpful, let me know where you are stuck and I will keep trying to help!