cpan[1]> install XML::LibXML
CPAN: Storable loaded ok (v2.18)
Going to read '/root/.cpan/Metadata'
  Database was generated on Sat, 05 Jun 2010 04:27:23 GMT
CPAN: YAML loaded ok (v0.70)
Going to read 86 yaml files from /root/.cpan/build/
CPAN: Time::HiRes loaded ok (v1.9711)
DONE
Restored the state of none (in 2.0500 secs)
Running install for module 'XML::LibXML'
Running make for P/PA/PAJAS/XML-LibXML-1.70.tar.gz
  Has already been unwrapped into directory /root/.cpan/build/XML-LibXML-1.70-IIX0Tb
  No 'Makefile' created
, won't make
Running make test
  Make had some problems, won't test
Running make install
  Make had some problems, won't install

対処法

# su -        # rootになる
# cd /root/.cpan/build/XML-LibXML-1.70-IIX0Tb
# perl Makefile.PL      # Makefile.PLを実行　→　エラーが出る
# apt-get install libxml2-dev       # ライブラリをインストール
# perl Makefile.PL       #  Makefile.PLを実行　→　またエラーが出る
# apt-get install libxml-libxml-perl      # ライブラリをインストール
# perl Makefile.PL       # 成功！！
# make
# make test
# make install
# update-perl-sax-parsers       # 一応。
# cpan

cpan>  install XML::libXML       # 成功！
cpan>  install Web::Scraper      # 成功！