Docbook sends all sorts of errors with several different complations. The main one that I have found is esound See bug http://bugs.gentoo.org/show_bug.cgi?id=128952 for more info. I have tried to re-emerge all of the sgml files that it looks to be accessing. I have also re-emerged jade. I then tried to unmerge and re-emerge them with no change. If you need more info just let me know.
Hmmm, why are you filing a new bug? *** This bug has been marked as a duplicate of 128952 ***