Yes, I did hit the "Apply" button

The font settings as Stephen pointed out is another setting that gets set back to the default with each new KDE session.

I had this problem with Mozilla not storing any bookmarks beyond the current session and fixed that by changing the group owner of the mozilla folder tree.

Perusing around the KDE Control Center, I noticed that all the fonts are stored in the /home/knoppix/.kde/ firectory even though I am logged in as a different user (a user account that I created). For this reason it seems to me that the KDE preferences are being stored in some directory to which my user does not have permissions, and thus my settings do not get persisted beyond the current session. Can someone verify whether this is true or not, or tell me how I can verify (and hopefully change) this?

Your help is greatly appreciated.