Adjusting Shared Memory with sysctl.conf not working?

[Doug Graham <duggram(at)gmail(dot)com>]

I'm trying to install Postresql on my Mac Book Pro which has 4GB ram and
runs OS X 10.5.6. Postgres won't install because it says I don't have more
than 32MB of shared memory. So as they tell you in their readme I created a
file /etc/sysctl.conf with these lines:

kern.sysv.shmmax=16777216
kern.sysv.shmall=16777216
kern.sysv.shmmin=1
kern.sysv.shmmni=4096
kern.sysv.shmseg=8

Reboot multiple times. Here's what shared memory I have running now:

DougMBP:~ duggram$ sysctl -a | grep shm
kern.exec: unknown type returned
kern.sysv.shmall: 16777216
kern.sysv.shmseg: 8
kern.sysv.shmmni: 4096
kern.sysv.shmmin: 1
kern.sysv.shmmax: 4194304

Which is more than Postgres says is required. Any suggestions on what I need
to do to get Postgres to install?

Any advice appreciated, Doug