libxml2 отсутствует при установке devkit nokogiri gem (windows)

У меня было много проблем с этим гемом, поэтому я прочитал, что мне пришлось использовать де 1.5.0-бета.

Поскольку я использую Windows, я скачал DevKit. Но когда я побежал:

gem установить nokogiri --pre --with-xml2-lib --with-xslt-lib

Я получил:

Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
ERROR:  Error installing nokogiri:
        ERROR: Failed to build gem native extension.

        C:/Ruby187/bin/ruby.exe extconf.rb --with-xml2-lib --with-xslt-lib --pla
taform=ruby
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=C:/Ruby187/bin/ruby
        --with-zlib-dir
        --without-zlib-dir
        --with-zlib-include
        --without-zlib-include=${zlib-dir}/include
        --with-zlib-lib
        --without-zlib-lib=${zlib-dir}/lib
        --with-iconv-dir
        --without-iconv-dir
        --with-iconv-include
        --without-iconv-include=${iconv-dir}/include
        --with-iconv-lib
        --without-iconv-lib=${iconv-dir}/lib
        --with-xml2-dir
        --without-xml2-dir
        --with-xml2-include
        --without-xml2-include=${xml2-dir}/include
        --with-xml2-lib=${xml2-dir}/lib
C:/Ruby187/lib/ruby/1.8/mkmf.rb:1177:in `dir_config': private method `split' cal
led for true:TrueClass (NoMethodError)
        from extconf.rb:87


Gem files will remain installed in C:/Ruby187/lib/ruby/gems/1.8/gems/nokogiri-1.
5.0.beta.4 for inspection.
Results logged to C:/Ruby187/lib/ruby/gems/1.8/gems/nokogiri-1.5.0.beta.4/ext/no
kogiri/gem_make.out

Что я могу сделать?