Linux Mint 10 (julia): starting Postrgesql 8.4 at booting up

required scripts have been added to :

/etc/init.d
/etc/rc2.d

while installing Postgresql.
Despite this server doesn't start at booting up. when i try to execute
script from rc2.d manually i get message: "chmod: can't change
permissions of `/var/run/postgresql'. it is permitted". as root works
properly .
here there are permissions of the folder:
drwxrwsr-x 2 postgres postgres 40 2011-11-06 07:57 postgresql

any hints?

thx in advance

Peter