Besides my own Outlook 2007 calendar, I am also the "owner" of a public
calendar to which several others have editing privileges. I can add and
change appointments to the public calendar, but when I go to print it, my
updates are not there even though they are visible on my Outlook screen.
What can I do to get CPA to print the updated appointments?

My understanding is that CPA does not handle merged calendars very
well.

You may want to consider using a Outlook Calendar printing app called
Wincalendar instead. It allows you to render your Outlook calendar in
various MS Word or Excel formats + it supports many Outlook calendars
merged into one. See here for more info:
http://www.wincalendar.com/Outlook-Calendar-Import.htm
http://www.wincalendar.com/calendar-maker.html