Nah, not to worry... Overblaming yourself is actually a good thing. Those that do the opposite tend to fall in the arrogant category and that's when code really begins to suffer.

I ran the code you provided and it's really odd to me. I cannot, for the life of me, figure out why Ken wanted to create six copies of the same hierarchy with all people at all levels reporting to the same supervisor.

I agree with Lynn, as well. Just because someone forwards a book, doesn't mean they even looked at the content never mind actually doing any technical reviews. Even some authors don't check their own code and not all technical reviewers are good technical reviewers.