The problem with the recurring event not showing up correctly was on my Mac. So I decided to delete all instances of a recurring appointment and just make one and copy & paste. In the process of deleting all the instances, ALL the appointments disappeared.
They are still on the school server, and I can get that file, but when I try to open it on my Mac, it says it'a an invalid file.
But all the dates are there - I can see that in BBEdit.
(I did decide to upgrade to the new PHP iCalendar, but that was not the source of the problem.)