I suppose that if you are installing PHP on a Linux Box you can just forget this file, because it's a better release for MicroZoft OS...
FYI: I've installed the "basic" PHP 4.2.3 dist on IIS (w2k), and I don't have got major problem to read through out the book. (I didn't read the Â§16 Generating Graphics...)
However this "basic" PHP 4.2.3 for MS OS distribution it's obviously not for production servers (as they tell in the readme file). I've experienced some non-reproductible very funny errors when this dll is interpreting my pages!
PS.: after just only 25 little pages, were you so tired that you didn't noticed the BIG Title on page 24 saying : Installing PHP4 Alongside IIS ????