SOAP services using savon is not working

I have installed savon gem in windows 7 with ruby 1.8. It shows in gem list

But when I give

require 'rubygems'
require 'savon'

It gives following error

NameError: uninitialized constant Savon
        from ./savon.rb:3
        from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
        from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `re开发者_如何转开发quire'
        from (irb):1

any solutions?

your local file being named "savon.rb" might be conflicting with savon gem's file named "lib/savon.rb"