KOffice depends upon ImageMagick and the ebuild depends upon imagemagic.sourceforge.net/imagemagick-5.4.7-1.tar.bz2. However, SourceForge no longer has that version of this software available. 5.4.7-4 is the closest currently available.
imagemagick-5.4.7.4.ebuild is in portage now. thanks for catching that :)
*** Bug 9727 has been marked as a duplicate of this bug. ***