Gem install libxml-ruby - extconf failure: need zlib

Hi,
I am getting below error while installing libxml-ruby gem. As per
peoples
suggestion on other threads, I tried to install 32 bit version of
libxml-ruby gem, but still getting the same error.

I am using windows 7 and Ruby 1.9.3.

Please help me out here as I need to make the old project run on my new
job.

c:/RailsInstaller/Ruby1.9.3/bin/ruby.exe extconf.rb
checking for socket() in -lsocket… no
checking for gethostbyname() in -lnsl… no
checking for atan() in -lm… yes
checking for inflate() in -lz… no
checking for inflate() in -lzlib… no
checking for inflate() in -lzlib1… no
checking for inflate() in -llibz… no
*** 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:/RailsInstaller/Ruby1.9.3/bin/ruby
–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-zlib-dir
–without-zlib-dir
–with-zlib-include
–without-zlib-include=${zlib-dir}/include
–with-zlib-lib
–without-zlib-lib=${zlib-dir}/lib
–with-socketlib
–without-socketlib
–with-nsllib
–without-nsllib
–with-mlib
–without-mlib
–with-zlib
–without-zlib
–with-zliblib
–without-zliblib
–with-zlib1lib
–without-zlib1lib
–with-libzlib
–without-libzlib
extconf failure: need zlib