It is SELinux that is causing your error. The problem is that it sets security context on all files.
If you type: ls -laZ on the default /usr/local /var/rw folder, what permissions are returned?
Mine look like this-
[grahama@p550 ~]$ ls -laZ /usr/local/nagios/var/rw
drwxrwsr-x nagios nagcmd system_u:object_r:httpd_sys_script_rw_t .
drwxrwxr-x nagios nagios system_u:object_r:usr_t ..
prw-rw---- nagios nagcmd user_u:object_r:httpd_sys_script_rw_t nagios.cmd
Sorry about the wrap.
there is another way to temporarily disable SELinux - simply type setenforce 0 to disable on the fly. 1 will enable it again.
chcon will set these permissions.