Ok, run the command "/etc/rc.d/rc.firewall".
Does it load without any strange errors? Yes, try these tests:
ip_tables.o: Device or resource busy
Run the command "/sbin/lsmod" and make sure the module "ipchains.o" is NOT installed. If it is installed, your machine (most likely Redhat-7.x based) is probably trying to load an IPCHAINS ruleset which is incompatible with IPTABLES.
To disable this from happening in the future, run the command:
chkconfig --level=2345 ipchains off
To remove the "ipchains" module without rebooting, run the command:
No such file: Did you copy this rc.firewall file from a DOS machine? Load the rc.firewall file in a binary editor (vim -b /etc/rc.d/rc.firewall) and make sure that every line is NOT finished with a ^M.