Igor, thank you.
Earlier this year, I added the remi repo in order to get PHP 5.4 based on http://kb.odin.com/en/115833
I removed /etc/yum.repos.d/remi.repo and /var/cache/yum/remi/ and tried again and got the same result.
I rebooted (140 day uptime) just in case. Same result again...
I just applied yum updates and then attempted Plesk microupdates on a Mediatemple dv4 VPS running CentOS release 5.11.
I ran the 'up' alias (as I have done many times with success):
alias up='/usr/local/psa/admin/sbin/autoinstaller --select-product-id plesk --select-release-current...
Since I installed the Plesk Billing module, now Plesk goes away after a few minutes of clicking around configuring it. I have not figured out if it's a specific action which causes the shutdown, and the associated log doesn't seem to say much:
2013-04-05 12:42:27: (server.c.1543) server...