ctrmc subsystem missing after ML upgrade

After upgrading from AIX 5.3 ML03 to ML04 (and possibly from/to other levels also), for some reason the ctmrc subsystem is no longer present. This is a problem for LPARs because all DLPAR functionality is lost. To re-create and start the subsystem, execute these commands:

/usr/sbin/rsct/bin/rmcctrl -a
/usr/sbin/rsct/bin/rmcctrl -s