Une bue wrote:
> ~%> sudo ln -s direct.rb /opt/local/lib/ruby/site_ruby/1.8/yt/direct

Try adding a .rb to the symlink:

sudo rm -f /opt/local/lib/ruby/site_ruby/1.8/yt/direct
sudo ln -s direct.rb /opt/local/lib/ruby/site_ruby/1.8/yt/direct.rb

Regards,
Jordan