I am using Sketchup 7.1 and the latest version as attached in the post above. I used the example.dat file that the pdf mentions and got the following error on the ruby console

Error; #<TypeError; nil can't be coerced into Length>
(eval);305;in `*'
(eval);305;in `draw_geometry'
(eval);302;in `each'
(eval);302;in `draw_geometry'
(eval);217;in `onLButtonUp'

Any clue on what the problem might be? I am on Windows XP.