permission problem

[Blaq hacka]

hi  all   [root@hacka test]# ls -al /etc/rc.d/rc.local -rwxr-xr-x   1 root     root          961 Oct 15 10:17 /etc/rc.d/rc.local [root@hacka test]# chmod 0600 /etc/rc.d/rc.local chmod: /etc/rc.d/rc.local: Operation not permitted i want to edit this  file  .. any ideas  on what i  should  do !!i have  tried  most  chmod  options   but no hope  ... can  any one  set  some  light  on waht i should  do !!!!   blaq hacka