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.


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:

Gem files will remain installed in
for inspection.
Results logged to