Solaris 7 x86 error

Folks:

I get the following errors when trying to start up Postgres ('postmaster
-S') on a Solaris 7 x86 machine:

IpcMemoryCreate: shmget failed (Invalid argument) key=5432010, size=120,
permission=700
IpcMemoryIdGet: shmget failed (No such file or directory) key=5432010,
size=120, permission=0
IpcMemoryAttach: shmat failed (Invalid argument) id=-2
FATAL 1: AttachSLockMemory: could not attach segment

The shared memory settings in /etc/system are:

set shmsys:shminfo_shmmax=50331648
set shmsys:shminfo_shmmin=200
set shmsys:shminfo_shmmni=200
set shmsys:shminfo_shmseg=200
set semsys:seminfo_semmap=250
set semsys:seminfo_semmni=500
set semsys:seminfo_semmns=500
set semsys:seminfo_semmsl=500
set semsys:seminfo_semmnu=500
set semsys:seminfo_semume=100

Compiler was gcc 2.95.1.

A truss of the postmaster process shows the following:

shmget(5432010, 120, 0700|IPC_CREAT) Err#22 EINVAL
IpcMemoryCreate: shmget failed (Invalid argument) key=5432010, size=120,
permis\
sion=700write(2, " I p c M e m o r y C r e".., 87) = 87

write(2, "\n", 1) = 1
shmget(5432010, 120, 0) Err#2 ENOENT
IpcMemoryIdGet: shmget failed (No such file or directory) key=5432010,
size=120\
, permission=0write(2, " I p c M e m o r y I d G".., 93) = 93

write(2, "\n", 1) = 1
shmat(-2, 0, 0) Err#22 EINVAL

Am I doing something obviously wrong? Many thanks for advice.

(BTW, does the search function in the mailing list message archive work?
Trying simple, obvious search values like 'solaris' or 'linux' produces no
hits.)

-David.