Error when I try to run initdb under cygwin. Plz help me...

Hi all...
I'm newbie with cygwin but I'm receiving a error message when I try to run
'initdb' here...

Look:
I'm using win98 and I want to run postgresql...
I installed cygwin from Internet and everything goes fine...
I open a bash shell and run 'ipc-daemon &'... ok...
When I run 'initdb -D /var/psql' the error:

The files belonging to this database system will be owned by user "dug".
This user must also own the server process.
The database cluster will be initialized with locale C.
fixing permissions on existing directory /var/psql... ok
creating directory /var/psql/base... ok
creating directory /var/psql/global... ok
creating directory /var/psql/pg_xlog... ok
creating directory /var/psql/pg_clog... ok
selecting default max_connections... 10
selecting default shared_buffers... 50
creating configuration files... ok
creating template1 database in /var/psql/base/1...
FATAL: could not create shared memory segment: Function not implemented
DETAIL: Failed system call was shmget(key=1, size=1081344, 03600).
initdb: failed

What's wrong? some package that I don't install ?
what now ?

thanx for any hint

Flávio Henrique