When emerging vanilla-sources-2.4.22, the source is unpacked to /var/tmp/portage/vanilla-sources-2.4.22/linux-2.4.22/ The ebuild then proceeds to look in the catalogue /var/tmp/portage/vanilla-sources-2.4.22/linux-2.4.22-vanilla/ and consequently exits with an error about catalogue not found. Creating an appropriate soft link to ensure the existense of the sought after catalogue is a work-around. This bug may possibly be related to http://bugs.gentoo.org/show_bug.cgi?id=33045
this should be fixed in cvs now