Can't install gnome2 - docbook-utils is broken

[Jim Trigg]

Running 7.0-RELEASE; attempting to install gnome2 from ports.  (Note:
I tried installing from packages on the distribution CDs and
upgrading; that was a worse nightmare...)

First, docbook-utils insists that docbook-310 is not installed when it
is.  I tracked that one down:

/usr/ports/textproc/docbook-utils/Makefile:
19c19
<
${LOCALBASE}/share/sgml/docbook/3.1/docbook.dtd:${PORTSDIR}/textproc/docbook-310
\
---
>                 ${LOCALBASE}/share/sgml/docbook/3.1/dtd:${PORTSDIR}/textproc/docbook-310 \

Then, docbook-utils fails with the following error:
jade:../../doc/docbook-utils.sgml:1:55:W:cannot generate system
identifier for public text "-//OASIS//DTD DocBook V3.1//EN"
followed by a lot of subsequent errors about unknown entities.

How do I fix this?  I've already searched the archives, the bug
database, and the web with no useful results.

Thanks,
Jim Trigg