firewall help

Hi

I'm followng the instructions at this week's issue of LinuxJournal. They
have an article on how to set up the Net Filter firewall. The address is
http://www2.linuxjournal.com/cgi-bin/frames.pl/index.html

The instructions say to do "modprobe ip_tables" to insert and then "lsmod |
grep ip_tables" to verify. However, I cannot get past the first command. I
receive an error. Has anyone seen this error? Can you tell me what it
means? I rebooted and get the same message. Here it is:

[root@Shitty /root]# modprobe ip_tables
/lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o: init_module:
Device
or resource busy
Hint: insmod errors can be caused by incorrect module parameters, including
invalid IO or IRQ parameters
/lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o: insmod
/lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o failed
/lib/modules/2.4.2-2/kernel/net/ipv4/netfilter/ip_tables.o: insmod ip_tables
failed
[root@Shitty /root]#