As I have stated elsewhere--sorry it is not up on the site yet--the publisher put in "page 23" on the CD instructions for the new book (the Hidden Power of Photoshop Elements 3) when they meant the 23rd page of the book...it was a mistake. The password is in the introduction on an unnumbered page in a section on The Hidden Power Tools. That part I *did* write.
The proper forum for the question is the Hidden Power of Photoshop Elements 3.
http://retouchpro.com/forums/forumdisplay.php?f=163
The hiddenpower.com website will be updated shortly to include all errata. there is this and only two other minor issues. First, the hiddenelements.com website is spelled incorrectly on the book's cover (it was correct when i sent it); second, step 4 on page 50 should have you naming the layer Composite, not Luminosity.