pg_ctl won't start postgres, but postmaster will?!

I have had a lot of problems trying to install the postgres on a second
FreeBSD box. I installed it using the ports install, so that part of the
process went painlessly. however, when I tried to run the .sh script file
that was installed, I get nothing. The script's commands are:

chmod 600 ${logfile}
chown pgsql:pgsql ${logfile}
[ -x ${PGBIN}/pg_ctl ] && {
su -l pgsql -c \
"[ -d \${PGDATA} ] && exec ${PREFIX}/bin/pg_ctl start -s -w -l
${logfile}"
echo -n ' pgsql'

No errors, no messages, nothing. Then I tried to start pg_ctl by hand. I
su'd to pgsql, and typed:

/usr/local/bin/pg_ctl -D /pgdata -l /var/log/pgsql

and nothing, postmaster still doesn't start! If I type:

su -l pgsql -c exec "/usr/local/bin/postmaster -D /pgdata"

I get a "postmaster started successfully" reply, BUT postmaster STILL isn't
running.

The only way I can get postmaster to run is to first su into pgsql, then
type:

/usr/local/bin/postmaster -D /pgdata

Then it starts up fine! None of this makes any sense to me at all. On a side
note, even when postmaster is running, webmin says that postgres isn't
running, even tho I told it where the database is. Just one more thing
that's messed up. Any ideas as to why this isn't working?