FreeBSD web build failed on build-web.stream.freebsd.org

[User Www-data]

===> doc/articles/rc-scripting (all)
===> doc/articles/relaydelay (all)
===> doc/articles/releng (all)
===> doc/articles/releng-packages (all)
===> doc/articles/remote-install (all)
===> doc/articles/serial-uart (all)
===> doc/articles/solid-state (all)
===> doc/articles/vm-design (all)
===> doc/articles/wp-toolbox (all)
===> doc/books (all)
===> doc/books/arch-handbook (all)
===> doc/books/design-44bsd (all)
===> doc/books/dev-model (all)
===> doc/books/developers-handbook (all)
===> doc/books/faq (all)
===> doc/books/fdp-primer (all)
===> doc/books/handbook (all)
/usr/bin/grep '^<?xml version=.*?>' book.xml > book.parsed.xml.tmp
echo '<!DOCTYPE book PUBLIC "-//FreeBSD//DTD DocBook XML V4.5-Based Extension//EN" "../../../share/xml/freebsd45.dtd">' >> book.parsed.xml.tmp
==> Basic validation
env XML_CATALOG_FILES="file:///home/www/build/head/en_US.ISO8859-1/books/handbook/catalog-cwd.xml  file:///home/www/build/head/en_US.ISO8859-1/share/xml/catalog.xml  file:///home/www/build/head/share/xml/catalog.xml  file:///home/www/build/head/share/xml/catalog-common.xml  file:///usr/local/share/xml/catalog" /usr/local/bin/xmllint --nonet --noent --valid --xinclude --dropdtd /home/www/build/head/en_US.ISO8859-1/books/handbook/book.xml |  /usr/bin/grep -v '^<?xml version=.*?>' >> book.parsed.xml.tmp
/home/www/build/head/en_US.ISO8859-1/books/handbook/index.xml:344: parser error : Input is not proper UTF-8, indicate encoding !
Bytes: 0xA0 0x52 0x65 0x61
    <ulink url="#AEN9661" role="AEN9664">Acrobat Reader</ulink>
                                                ^
/home/www/build/head/en_US.ISO8859-1/books/handbook/index.xml:4790: parser error : chunk is not well balanced

^
/home/www/build/head/en_US.ISO8859-1/books/handbook/book.xml:306: parser error : Failure to process entity chap.index
  &chap.index;
              ^
/home/www/build/head/en_US.ISO8859-1/books/handbook/book.xml:306: parser error : Entity 'chap.index' not defined
  &chap.index;
              ^
*** [book.parsed.xml] Error code 1

Stop in /home/www/build/head/en_US.ISO8859-1/books/handbook.
*** [all] Error code 1

Stop in /home/www/build/head/en_US.ISO8859-1/books.
*** [all] Error code 1

Stop in /home/www/build/head/en_US.ISO8859-1.
*** [all-all] Error code 1

Stop in /home/www/build/head/en_US.ISO8859-1/htdocs/doc.
*** [all] Error code 1

Stop in /home/www/build/head/en_US.ISO8859-1/htdocs.
        7.12 real         4.09 user         3.25 sys