That's because 192.168.168.x/phpmyadmin is not a hostname!
if you use
Virtualhost {
Hostname = 192.168.168.x
WebsiteRoot = /var/www
StartFile = index.php
}
it should work. 192.168.168.x is your hostname. /phpmyadmin and /test are directories inside the virtualhost. Because your virtualhost points to /var/www, those paths should be available in /var/www. They probably already are.