Put the docbook tools from 
https://sourceforge.net/projects/triceps/files/docbook-for-1.0/ 
here.  Run "make" to download an extract them, or "make extract" just to
extract the already downloaded files.  

They are not a part of the basic distribution, to keep the Triceps package
smaller and the packages separate.  Besides, they're expected to stay the same
for a long while.