/usr/bin/hostid is missing from redhat 5.2, from util-linux-2.8-11 (along with some other binaries I might add). hostid was last seen in util-linux-2.7-15. Some commercial packages use hostid to determine licensing. The lack of hostid causes these commercial packages to fail.
This has been verified on a 5.2 box.
hostid is not deterministic on machines without unique hostids (suns do, PCs don't at the moment) so it was removed.