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