[postgres no lnger launches

Hi,

how do I troubleshoot postgres? It simply won't start any more. I cannot login, not locally nor remotely. I tried a couple of things without success.

bash-3.2$ ps -Ac | egrep postgres
bash-3.2$ /Library/PostgreSQL/9.1/bin/pg_ctl start -D /Library/PostgreSQL/9.1/data -l postgres.log
pg_ctl: another server might be running; trying to start server anyway
server starting
bash-3.2$ /Library/PostgreSQL/9.1/bin/pg_ctl start -D /Library/PostgreSQL/9.1/data -l postgres.log
pg_ctl: another server might be running; trying to start server anyway
server starting
bash-3.2$ /Library/PostgreSQL/9.1/bin/pg_ctl start -D /Library/PostgreSQL/9.1/data -l postgres.log
pg_ctl: another server might be running; trying to start server anyway
server starting
bash-3.2$ ps -Ac | egrep postgres

So sure enough that process claimed to might be starting does not end up being a process. Where do I look for what's actually going on?

This is the log output:
04.06.12 00:26:29,792 com.edb.launchd.postgresql-9.1: If the request size is already small, it's possible that it is less than your kernel's SHMMIN parameter, in which case raising the request size or reconfiguring SHMMIN is called for.
04.06.12 00:26:29,792 com.edb.launchd.postgresql-9.1: The PostgreSQL documentation contains more information about shared memory configuration.
04.06.12 00:26:29,793 com.apple.launchd: (com.edb.launchd.postgresql-9.1[1260]) Exited with code: 1
04.06.12 00:26:29,793 com.apple.launchd: (com.edb.launchd.postgresql-9.1) Throttling respawn: Will start in 10 seconds
04.06.12 00:26:30,000 kernel: nstat_lookup_entry failed: 2

It respawns every ten seconds and fails. Now this installation has been running for a few weeks now without a hiccup. I tried to enable remote login, I might have screwed up the pg_hba.conf file. So I copied the same file from an installation of another server I have on which things are running ok. I restarted but it continues to throw up those respawn messages and shared mem segmets stuff.

I changed the sysctl.conf file, but this neither made a difference. This unit has loads of memory....actually the messages seem to be rather bogus. Also, it worked fine, I didn't change the sysctl file before, it seems silly to assume that it just changes itself out of the blue and stops working. I installed nothing, there is no source I can assume to have done so. What can I do to make this server working again?

Thanks
Alex