operation not permitted error

If you are trying to change the permission say admin folder by chmod 755 admin/ but it is giving you  operation not permitted error  then  check for imutable
#  lsattr                        // it will show you all attributes under the current folder , so check if  folder is imutable or not  o/p :”  —-i——– ./admin”
# chattr -i admin/         // then remove that imutable attribute  with -I option
chattr -aui /usr/local/Zend/etc/php.ini