Require not working

Hi,

I installed the require ruby gems and it is there in the lib
directory ..

but when i tried to call it using require its not working

1) with irb: i tired require 'rubygems' its throwing me false
and for require 'scrubyt' its throwing the below given error message

LoadError: no such file to load -- parse_tree_reloaded
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
27:in `ge
m_original_require'
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
27:in `re
quire'
        from c:/ruby/lib/ruby/gems/1.8/gems/scrubyt-0.3.0/lib/
Scrubyt.rb:9
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
32:in `ge
m_original_require'
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
32:in `re
quire'
        from (irb):4

3) when i use it with rails....its throwing the error message