Good job Derek !
1) Now can you d/l and install gems from within Sketchup embedded Ruby ??
2) You are running OSX Lion, so I assume your machine is Intel based. I wonder why you need to add platform dir paths for a PowerPC (MacOS9) platform ??
3) The following dir paths should not have files in them, only subdirs. Why add them ??
" /Library/Ruby/Site"
" /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/vendor_ruby"
4) You also add the current working directory, ie: " ." (which can change from time to time, via calls to Dir.chdir in other author's plugins.) So, is this necessary for RubyGems ??
5) After require('rubygems') returns (sucessfully,) has it added any paths to the $LOAD_PATH array ??