Hi,
these lines belong to the Moodle 1.4.x theme config file. If you work with Moodle 1.5.x please use one of the themes designed for 1.5.x.
For an overview how to set up your own theme based on one of the standard themes please read the Moodle Theme Documentation.
Moodle uses CSS to style the pages. If you want to modify themes you need basic CSS skills.
I hope this helps
Urs