More "IpcMemoryCreate: shmget failed" errors

Hello again,

A couple of weeks ago I reported a problem installing both 7.0 and
7.0.2 where attempting to start "postmaster" produced an "IpcMemoryCreate:
shmget failed"-type error.

Tom Lane suggested I use the "ipcclean" application to remove
the "old shmem segments".

Running "ipcclean" with 7.0.2 gave "ipcclean: nothing removed" as
the result "but postmaster" still gave the same "IpcMemoryCreate: shmget
failed" error.

So ... I deleted this 7.0.2 installation and decided to go back to
6.5.3. This installed, but when trying to start "postmaster" I got:

----- - - -----
IpcMemoryCreate: shmget failed (Permission denied) key=5432010, size=120, permission=700
IpcMemoryAttach: shmat failed (Permission denied) id=130
FATAL 1: AttachSLockMemory: could not attach segment
----- - - -----

So, I ran ipcclean that comes with 6.5.3 which finished with no
messages, but "postmaster" still gives the "IpcMemoryCreate: shmget
failed".

Hence, I cannot run PostgreSQL on this system any more :(

Any suggestions? Is there a way that v7 could check for these old
segments from v6 and remove them? Is this even the problem here? Any
other ways to clear these suspected old segments at all?

Thanks for your time,

--
Sean Kelly <S(dot)Kelly(at)ncl(dot)ac(dot)uk>
"The best way to predict the future is to invent it" - Alan Kay