Looked at the logs for the first failed build, and found this:
(cd debian-tei-roma; debclean; debuild -i.svn -I.svn -uc -us) /bin/sh: debclean: not found /bin/sh: debuild: not found
These are in the package devscripts, so
sudo apt-get install devscripts. I'll try the build again.
Looking at the stylesheet failure, we're missing xsltproc, so
sudo apt-get install xsltproc. Then trying again, noticed I need debhelper, so
sudo apt-get install debhelper.