Thanks Andrew! I have an ATI Radeon video card. Ubuntu installed as default the first ATI driver down the list. My card was filed under the name "Radeon - ATI ...". Changing the driver fixed the problem.
(Maybe you should rename this thread to something more informative since my problem had nothing to do with the missing fonts in the end?)
Anyway, thanks a lot your swift reply and for a great and sensibly priced product (I like your book too)! If I would also get my infinite line howto question solved, I would be a happy man (until the next problem ;o)!
Ubuntu 7.10 | QCad 18.104.22.168