RSRUBY installation in Windows XP

I am using R-2.8.1 in my XP windows environment.

When i used gem to install i got the following error. Any help to
resolve is gratefully appreciated. Thanks

Note that i also tried with out remote option; i get the same error.

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C:\ruby\bin>gem install rsruby --remote
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 rsruby --remote
checking for main() in R.lib… no

ERROR: Cannot find the R library, aborting.
*** 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-R-dir
–without-R-dir
–with-R-include
–without-R-include=${R-dir}/include
–with-R-lib
–without-R-lib=${R-dir}/lib
–with-Rlib
–without-Rlib

Gem files will remain installed in
C:/ruby/lib/ruby/gems/1.8/gems/rsruby-0.5.1.1
for inspection.
Results logged to
C:/ruby/lib/ruby/gems/1.8/gems/rsruby-0.5.1.1/ext/gem_make.out

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