The warning in chapter 2 states that it's necessary to change some control files when qmail gives errors. However it doesn't say that qmail should be restarted after the changes. Sounds trivial but if you forget everything is a lot more difficult...
Steps to Reproduce:
1. try to following the warning message literally
qmail wasn't restarted so the error stays
replacing "Once you have, edit the configuration files in /var/qmail/control/. "
with "Once you have, edit the configuration files in /var/qmail/control/ and
restart qmail with /etc/init.d/svscan restart." seems usefull to me.
most of the control files are read upon every invocation of qmail so i dont think restarting them is required
i'll double check though
There should be no need to reload qmail - you should only need to restart when you actually upgrade. There are the odd exception here and there but I've never had any problems.
shouldnt need to restart qmail