problem starting 2 postmasters on sun solaris2.6

Hi.

I have spent most of a day trying to get 2 postmasters to run on a solaris2.6 sun.
I have searched thru the admin mail archives but have not been able to find
anything that has helped at this point.

I am currently trying to run 2 postmasters (v6.5.3) one compiled with defaults
and the other with a "-- with-pgport=5400" (arbitrary number). I am using
a "-p 5400" option to start the 2nd postmaster and am setting the PGPORT
and other related PG variables to keep the 2 postmasters separated.

I am able to start one or the other separately but NOT both. I get error messages
to the effect:
---------------------------------------------------
FindExec: found "/opt/local/postgres-6.5.3_5400/bin/postgres" using PATH
binding ShmemCreate(key=5265c1, size=1073152)
IpcSemaphoreCreate: semget failed (No space left on device) key=5400015, num=16,
permission=600
proc_exit(3) [#0]
shmem_exit(3) [#0]
exit(3)
------------------------------------------------------

I have seen references to changes for /etc/systems file, but the few examples did
not seem to work for me - perhaps because I did not have the right values?

Can anyone direct me to some definitive documentation on how to get more than one
postmaster running on a sun solaris system?

Any help would be appreciated.
thanks,
John Uhlig.