i had this error when I run " ruby setup.rb"

************* 

   Successfully built RubyGem
  Name: sources
  Version: 0.0.1
  File: sources-0.0.1.gem
Removing old RubyGems RDoc and ri...
Installing rubygems-0.9.4 ri...

lib/rubygems/command_manager.rb:147:59: Skipping require of dynamic string: "rubygems/commands/#{command_name}_command"

lib/rubygems/digest/md5.rb:16:15: Couldn't find MD5. Assuming it's a module

lib/rubygems/gem_commands.rb:192:49: Skipping require of dynamic string: "rubygems/commands/#{name}_command"
Installing rubygems-0.9.4 rdoc...

lib/rubygems/command_manager.rb:147:59: Skipping require of dynamic string: "rubygems/commands/#{command_name}_command"

lib/rubygems/digest/md5.rb:16:15: Couldn't find MD5. Assuming it's a module

lib/rubygems/gem_commands.rb:192:49: Skipping require of dynamic string: "rubygems/commands/#{name}_command"

As of RubyGems 0.8.0, library stubs are no longer needed.
Searching $LOAD_PATH for stubs to optionally delete (may take a while)...
...done.
No library stubs found.
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please tell me what happen