I installed a new zimbra server & everything was perfectly installed but as soon as i restarted it mta is not starting.....i again installed it on new system but same thing happens

following error in zimbra.log

Sep 30 12:45:52 zimbra postfix/postfix-script[10456]: warning: not owned by root: /opt/zimbra/data/postfix/spool
Sep 30 12:45:52 zimbra postfix/postfix-script[10463]: warning: not owned by root: /opt/zimbra/postfix-2.6.7.2z/conf/main.cf
Sep 30 12:45:52 zimbra postfix/postfix-script[10464]: warning: not owned by root: /opt/zimbra/postfix-2.6.7.2z/conf/master.cf
Sep 30 12:45:52 zimbra postfix/postfix-script[10467]: warning: not owned by postfix: /opt/zimbra/data/postfix/./spool/maildrop/606B628F32D
Sep 30 12:45:52 zimbra postfix/postfix-script[10468]: warning: not owned by postfix: /opt/zimbra/data/postfix/./spool/maildrop/5F7FB28F32E
Sep 30 12:45:52 zimbra postfix/postfix-script[10469]: warning: not owned by postfix: /opt/zimbra/data/postfix/./spool/pid/inet.127.0.0.1:10025
Sep 30 12:45:52 zimbra postfix/postfix-script[10482]: starting the Postfix mail system
Sep 30 12:45:52 zimbra postfix/master[10483]: fatal: bind 0.0.0.0 port 25: Address already in use


Sep 30 07:23:00 zimbra postfix/postqueue[17920]: fatal: Queue report unavailable - mail system is down

Any help is appreciated