I am having trouble setting up IP maquerading. I have Linux Kernel 2.4 and IPtables 1.2.5. I am trying to run the firewall rc-firewall-2.4 and am getting these messages when the script is run

iptables v1.2.5:: can't initialize iptables 'filter' :iptables who ? (do you need to insmod)?
it ives that message for several files and it also gives
Perhaps your iptables or your kernel need to be upgreaded.
and
/lib/modules/2.4.18-5/kernel/net/ipv4/netfilter/ip_tables.o
: init_module: Device or resources are busy
iand finally it says
Hint: insmod errors can be caused by incorrect modules parameters, including invalid IO or IRQ parameters

Also should both my ethernet cards in my Linux box be set on DHCP or should on have the adrees statically set?