stgit version 0.15-1 failed to build on i386

stgit version 0.15-1 failed to build on i386
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110329/+buildjob/2411032

Direct link to the build log: https://launchpad.net/ubuntu/+archive/test-rebuild-20110329/+buildjob/2411032/+files/buildlog_ubuntu-natty-i386.stgit_0.15-1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 1176 lines into the build log:

../stg-build --asciidoc uncommit > stg-uncommit.txt
asciidoc --unsafe -b xhtml11 -d manpage -f asciidoc.conf stg-uncommit.txt
../stg-build --asciidoc undo > stg-undo.txt
asciidoc --unsafe -b xhtml11 -d manpage -f asciidoc.conf stg-undo.txt
../stg-build --asciidoc unhide > stg-unhide.txt
asciidoc --unsafe -b xhtml11 -d manpage -f asciidoc.conf stg-unhide.txt
asciidoc --unsafe -b xhtml11 -d article -a toc -f tutorial.conf \
                 tutorial.txt
asciidoc: ERROR: tutorial.txt: line 2: only book doctypes can contain level 0 sections
make[2]: *** [tutorial.html] Error 1
make[2]: Leaving directory `/build/buildd/stgit-0.15/Documentation'
make[1]: *** [doc] Error 2
make[1]: Leaving directory `/build/buildd/stgit-0.15'
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110408-1455
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/stgit-0.15