I don't know whether this is known bug. It is the first thing I come 
across when installing KDE3, so I can imagine it is.

kubuntu-desktop-kde3 depends on ttf-bitstream-vera but it's not 
available anymore in karmic as you can see here:
http://packages.ubuntu.com/nl/jaunty/ttf-bitstream-vera

Here is a patch:
http://haar.student.utwente.nl/~julius/patches/no_ttf-bitstream-vera.patch

I just removed the package from the dependencies. This allows me to 
install everything, but somehow also brings in some KDE4 packages on my 
system. Another option would be to add this package to the KDE3 repository.