PostgreSQL running in FreeBSD jail corrupts PostgreSQL running on the host system

I'm having some problems. Hopefully there are some FreeBSD folks here
that can help me out, if not, I'll try the FreeBSD lists next.

I'm running Postgres 7.4 installed from a just cvsupped FreeBSD ports.
I've got a production machine that's going to need a lot of upgrades, and
I want to test them out prior to upgrading the production environment.
So I built a jail on the production machine to install the new software
in and test prior. Seems logical, right?

Anyway, I set security.jail.sysvipc_allowed=1 so Postgres can run in the
jail, but every time I start Postgres in the jail, the Postgres running
in the host environ goes wacky. If I try to connect with psql, I get
the following error:

psql: FATAL: semctl(65542, 0, SETVAL, 0) failed: Invalid argument

This is FreeBSD 5.1-p17 (I can't upgrade to 5.2.1 until the em driver is
fixed ... but if someone knows for sure that this is fixed in 5.2.1, I'll
push harder to get that driver fixed!)

Anyone have any idea what's going wrong here? Or what I can do to fix
it?

--
Bill Moran
Potential Technologies
http://www.potentialtech.com