I just started reading the book.
My first action was to install the sample sites on my computer.
I was not to impressed by the installation program.
Firstly, it refused to run on Debian Linux 2.0 at all:
klemme@moa:/cdrom> ./install/install
./install/install: Permission denied.
It turned out that there are \r\n codes in the file. The command
tr \\r " " < ~/tmp/install > ~/tmp/install3
fixed that problem.

The next problem ist that the parameter substitution by the installation script is faulty.
Server name 2 is substituted for the administrator of server 1
Try this one:
sed -e "s?webuser?$WEBUSER?" \
-e "s?webgroup?$WEBGROUP?" \
-e "s?www.butterthlies.com?$S1NAME?" \
-e "s?sales@butterthlies.com?$S1ADMIN?" \
-e "s?sales.buttherthlies.com?$S2NAME?" \
-e "s?sales_mgr@butterthlies.com?$S2ADMIN?" \
-e "s?sales-IP.butterthlies.com?$S3NAME?" \
-e "s?/usr/www?$SITES?" < $X > $X.xxx
I personaly think the path to the apache binary should be adapted as well, since many systems come with pre-installed binaries in various places.
Add a
-e "s?httpd?/usr/sbin/apache?"
to the substitution (and adapt it to your path).

Otherwise:
Happy reading
Michael