First, if rpm crashes or is killed, you can just remove the locks in /var/lib/rpm (files beginning with underscores).
True -
But the only times I've seen rpm segfault is on a machine with broken memory, so I'd advise you run the memory tester from www.memtest86.com before your system is really hosed.
Unfortunately I've seen it happen on most of the systems where I've installed RH 8 or 9 -
Upgrading to the rpm-4.2-1 packages which were mentioned on this list seems to fix the rpm problems here -
Joe