The scons build for kdissert needs COPY not symlink the documentation files.
Otherwise, the install step copies the newly built KDE-style documentation into
/usr/kde/3.4/share/doc/HTML/en/kdissert (for example) and two of the files are
actually symlinks to the /var/tmp/portage tree where the product was built!
This was the kdissert-1.0.5 ebuild.
I looked a bit deeper and it looks like bksys/generic.py has
lenv.SetOption('duplicate', 'soft-copy')
which causes soft links (symlinks) to be used rather than copying the files.
I changed it to
lenv.SetOption('duplicate', 'copy')
and it fixed my problem.