cannot initdb

I installed 7.1.3 from ports on FreeBSD 4.2 and when I tried to initdb,
it failed:

su -l pgsql -c initdb
This database system will be initialized with username "pgsql".
This user will own all the data files and must also own the server process.

Creating directory /usr/local/pgsql/data
Creating directory /usr/local/pgsql/data/base
Creating directory /usr/local/pgsql/data/global
Creating directory /usr/local/pgsql/data/pg_xlog
Creating template1 database in /usr/local/pgsql/data/base/1
IpcSemaphoreCreate: semget(key=1, num=17, 03600) failed: Function not implemented

initdb failed.
Removing /usr/local/pgsql/data.
Removing temp file /tmp/initdb.16303.

What does the IpcSemaphoreCreate line mean? Thanks,

Joe