ERROR: Failed to build gem native extension

Hi,
I'm trtying to install postgress v0.7.9.2008.01.28 gems:

C:\>gem install -v=0.7.9.2008.01.28 postgres
Building native extensions. This could take a while...
ERROR: While executing gem ... (Gem::Installer::ExtensionBuildError)
    ERROR: Failed to build gem native extension.

ruby extconf.rb install -v=0.7.9.2008.01.28 postgres
checking for main() in /ms/libpq.lib... no
Could not find PostgreSQL build environment (libraries & headers):
Makefile
not
created
*** 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
        --srcdir=.
        --curdir
        --ruby=c:/ruby/bin/ruby
        --with-pgsql-dir
        --without-pgsql-dir
        --with-pgsql-include
        --without-pgsql-include=${pgsql-dir}/include
        --with-pgsql-lib
        --without-pgsql-lib=${pgsql-dir}/lib
        --with-/ms/libpqlib
        --without-/ms/libpqlib

Gem files will remain installed in
c:/ruby/lib/ruby/gems/1.8/gems/postgres-0.7.9
.2008.01.28 for inspection.
Results logged to
c:/ruby/lib/ruby/gems/1.8/gems/postgres-0.7.9.2008.01.28/ext/g
em_make.out

The mkmf.log file has following info:

have_library: checking for main() in /ms/libpq.lib...

You need to download windows-compiled gem with sth like 'mswin32' in
the name, becouse you use windows, don't you?
Look here:
http://wiki.rubyonrails.org/rails/pages/PostgreSQL (scroll down and
then...)
http://glauche.de/2007/12/21/installing-native-postgres-gem-for-ruby/