The sections on PHP that cover what you can do with PHP 6 that isn't supported in PHP 5 will not be relevant until PHP 6 is actually released and assumes that when it is released that it will work the way the book suggests. The mySQL section's only flaw that I could find is in failing to distinguish between logical normalisation of a database and those things that are then altered for a physical implementation of the database. While mySQL may work more efficiently with integers for primary keys the presented database certainly doesn't require those fields be added in order to normalise the data as there are perfectly adequate text fields that could be used as the keys during normalisation.
The books main failings are in the peripheral material. The author uses a transitional XHTML doctype throughout the book where a transitional doctype is not really the right choice for new web pages but is intended primarily for updating existing web pages without needing to rewrite them completely. Also there is no reason presented as to why an XHTML eather than an HTML doctype was chosen and for most readers an HTML strict doctype would be the most appropriate choice. The actual HTML is fairly peripheral to the main content of the book though so that someone who properly understands HTML can easily substitute the correct doctype in order to use the book.
This article written by Stephen Chapman, Felgall Pty Ltd.