Hy guys I got an error trying to install Rails on Windows XP /SP2

C:\rubydev\ruby >gem install rails --include-dependencies
ERROR: While executing gem ... (Gem::RemoteFet cher::FetchErro r)
getaddrinfo: no address associated with hostname.(Socke tError)

I have these Software Installed already:

-- Apache Web Server
-- MySQL 5.0
-- Ruby 1.8.5

What Can I do..???...