[CentOS] Error dovecot restart

Mon Jun 11 10:05:15 UTC 2012
Muhammad A. Fatahna <mafatahna at gmail.com>

Dear all,

i have a problem when install dovecot on CentOS 5, below my configuration

[root at mail home]# vim /etc/dovecot-sql.conf
driver = mysql
connect = host = localhost dbname=postfix user=mail password=password
default_pass_scheme = PLAIN
password_query = SELECT password FROM mailbox WHERE username = '%u'

[root at mail home]# vim /etc/dovecot.conf
log_path = /var/log/dovecot.log
auth_username_format = %Lu

passdb sql {
args = /etc/dovecot-sql.conf

userdb static {
args = uid=501 gid=501 home=/home/vmail/%d/%n

[root at mail home]# service dovecot restart
Stopping Dovecot Imap:                                     [FAILED]
Starting Dovecot Imap: Error: Can't write to log directory /var/log:
Permission denied
Fatal: Invalid configuration in /etc/dovecot.conf

i have try searching but i don't see step fix it,