unable to createuser in postgres 8.2.5 opensolaris

I initialized a database directory and it started fine. But when I tried to
create user I got this error.
Can you tell what is wrong?
thanks

createuser --superuser --createdb --createrole -P postgres
Enter password for new role:
Enter it again:
createuser: could not connect to database postgres: server closed the
connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.

the logfile is here:

LOG: could not bind IPv6 socket: Cannot assign requested address
HINT: Is another postmaster already running on port 5432? If not, wait a
few seconds and retry.
LOG: database system was shut down at 2007-11-18 19:50:38 PST
LOG: checkpoint record is at 0/42CC84
LOG: redo record is at 0/42CC84; undo record is at 0/0; shutdown TRUE
LOG: next transaction ID: 0/593; next OID: 10820
LOG: next MultiXactId: 1; next MultiXactOffset: 0
LOG: database system is ready
LOG: setsockopt(TCP_NODELAY) failed: Option not supported by protocol