initdb problem (Win2K Pro, cygwin)

Hi all,
When I try to run 'initdb' in a cygwin environment, I got this output:

$ /usr/local/postgresql7.4.1/bin/initdb -d -D
/usr/local/postgresql7.4.1/data

Running in debug mode.

initdb: internal variables:
PGDATA=/usr/local/postgresql7.4.1/data
datadir=/usr/local/postgresql7.4.1/share
PGPATH=/usr/local/postgresql7.4.1/bin
ENCODING=
ENCODINGID=0
POSTGRES_SUPERUSERNAME=laohuang
POSTGRES_BKI=/usr/local/postgresql7.4.1/share/postgres.bki
POSTGRES_DESCR=/usr/local/postgresql7.4.1/share/postgres.description

POSTGRESQL_CONF_SAMPLE=/usr/local/postgresql7.4.1/share/postgresql.conf.samp
le

PG_HBA_SAMPLE=/usr/local/postgresql7.4.1/share/pg_hba.conf.sample
PG_IDENT_SAMPLE=/usr/local/postgresql7.4.1/share/pg_ident.conf.sample
The files belonging to this database system will be owned by user
"laohuang".
This user must also own the server process.

The database cluster will be initialized with locale C.

fixing permissions on existing directory /usr/local/postgresql7.4.1/data...
ok
creating directory /usr/local/postgresql7.4.1/data/base... ok
creating directory /usr/local/postgresql7.4.1/data/global... ok
creating directory /usr/local/postgresql7.4.1/data/pg_xlog... ok
creating directory /usr/local/postgresql7.4.1/data/pg_clog... ok
selecting default max_connections... 10
selecting default shared_buffers... 50
creating configuration files... ok
creating template1 database in /usr/local/postgresql7.4.1/data/base/1...
DEBUG:
invoking IpcMemoryCreate(size=1081344)
FATAL: could not create shared memory segment: Function not implemented
DETAIL: Failed system call was shmget(key=1, size=1081344, 03600).
DEBUG: proc_exit(1)
DEBUG: shmem_exit(1)
DEBUG: exit(1)

initdb: failed

What is the problem? Is it related with path settings?

Thanks.

laohuang