Failing semctl

I have an intermittent problem with PostgreSQL 7.3.2 on Solaris 8.
The backend process crashes once in a while, with this in the database log:

... ...
2004-07-05 22:43:54 LOG: database system is ready
IpcSemaphoreInitialize: semctl(id=65615, 14, SETVAL, 0) failed:
Invalid argument
2004-07-06 09:19:03 LOG: server process (pid 23755) exited with exit code 1
2004-07-06 09:19:03 LOG: terminating any other active server processes
2004-07-06 09:19:03 WARNING: Message from PostgreSQL backend:
The Postmaster has informed me that some other backend
died abnormally and possibly corrupted shared memory.
I have rolled back the current transaction and am
going to terminate your database system connection and exit.
Please reconnect to the database system and repeat your query.
2004-07-06 09:19:03 WARNING: Message from PostgreSQL backend:
... ...

This problem may randomly pop up on any one of the few Pg servers
running on this host. I'm not sure whether this could be a kernel problem...
Do I need to look at the kernel configuration, installed patches, etc?

Any idea on why this could happen would be appreciated.
Mike.