Logrotate

Hi all,

I'm running postgresql 7.2.1 on a debian 3.0 machine and I want to do
some log rotation, but I'm having some problems. The configuration that
I'm using is:
In /etc/logrotate.d/postgres:
/var/log/postgres.log {
weekly
rotate 52
compress
delaycompress
notifempty
create 640 postgres postgres
sharedscripts
postrotate
/etc/init.d/postgresql restart > /dev/null
endscript
}

But when this is executed, always is returned the following error:

pg_ctl: Another postmaster may be running. Trying to start postmaster anyway.
pg_ctl: cannot start postmaster
Examine the log output.

Any sugestions !! What's wrong ?

Regards, Luis Sousa