I fixed the config, and now someone who couldn't see it this morning is seeing it again. Yippee.
Now I just need to find out:
* What user 'cron' runs as
* Whether cron is, in fact, running at all
* What the valid path(s) is/are for: the webserver, my user, and whatever cron runs as
* How to update the php.ini so it includes the PEAR extensions
* How to search my email, like I used to be able to do
* How to view the members of an email group
* How to set the 'from' address on my email, like I used to be able to do
* How to migrate my (restored) databases to the new MySql5 server without breaking everything
And by the way, when you specifically claim that one of the benefits of the email upgrade is "enhanced search capabilities", you might want to have, you know, enhanced the search capabilities somewhat.