xsltproc xpath undefined variable segfault on Docbook containing <footnote>

["Chris Chiasson" <chris@chiasson.name>]

Hello,
xsltproc is crashing on one of my books that has a footnote. It says
the stylesheet (docbook-xsl-1.69.1) has an XPath error with an
undefined variable. Here is the output:

libxslt/2006-03-11/bin/xsltproc --xinclude --nonet -o
/home/chris/sites/chris.chiasson.name/Engineering_Optimization/Engineering_Optimization.fo
xml/alpha/fo.xsl
/home/chris/sites/chris.chiasson.name/Engineering_Optimization/Engineering_Optimization.xmllint
Making portrait pages on USletter paper (8.5inx11in)
XPath error : Undefined variable
$ulink.footnotes != 0
                 ^
error: file file:///home/chris/sites/xml/docbook/docbook-xsl-1.69.1/fo/footnote.xsl
line 94 element number
Failed to compile predicate
make: *** [/home/chris/sites/chris.chiasson.name/Engineering_Optimization/Engineering_Optimization.pdf]
Segmentation fault

Info that may be relevant:

In an attempt to get around the xsltproc 1.15 problem of not handling
footnotes and the xsltproc 1.14 problem of note being compatable with
another package on my system, I'm using the 2006-03-11 snapshot of
xsltproc.

Does anyone have any ideas on how to fix this?

The same output courrs no matter what my settings are for
fop.extensions or fop1.extensions. ((0,0),(0,1),(1,0),(1,1))

Thank you for your time,
--
http://chris.chiasson.name/