I agree with Half_Elf -- build your own iptables script. The lokkit generated one is not meant to be manually customized.
Second, you're interested in opening your SMB shares only within your home LAN, right? You need to configure your iptables so that it allows all traffic originating from your LAN facing network card, but blocks unwanted intrusion from the internet facing network card.
Try this:
# !/bin/sh
# simple iptables script; check references below to harden it
# Red Hat: copy this script to /etc/rc.d/init.d and chmod +x
# Slackware: name this script iptables.sh and call from rc.local
# eth0 is internet facing network card
# eth1 is home LAN facing network card
# load iptables modules
/sbin/modprobe iptable_nat
/sbin/modprobe ip_conntrack
# enable ip forwarding
/bin/echo 1 > /proc/sys/net/ipv4/ip_forward
# flush tables
/sbin/iptables -F
/sbin/iptables -X
# enable masquerading to allow LAN internet access
/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
# forward home LAN traffic (email, counter-strike etc) to internet
/sbin/iptables -A FORWARD -i eth1 -o eth0 -m state --state NEW,ESTABLISHED -j ACCEPT
# allow SSH
echo -e " - Allowing EXTERNAL access to the SSH server"
/sbin/iptables -A INPUT --protocol tcp --dport 22 -j ACCEPT
# allow HTTP
echo -e " - Allowing EXTERNAL access to the HTTP server"
/sbin/iptables -A INPUT --protocol tcp --dport 80 -j ACCEPT
# block out internet intrusion on eth0
/sbin/iptables -A INPUT -i eth0 -m state --state NEW,INVALID -j DROP
/sbin/iptables -A FORWARD -i eth0 -m state --state NEW,INVALID -j DROP
# REFERENCES
# Netfilter iptables home --
http://www.netfilter.org/
# Frozen Tux iptables tutorial --
http://iptables-tutorial.frozentux.net/
# IP masquerade HOWTO --
http://tldp.org/HOWTO/IP-Masquerade-HOWTO/index.html
# SAMPLE SCRIPTS
# Arno's hardened iptables script --
http://freshmeat.net/projects/iptabl.../?topic_id=151
# Jay's homeLAN iptables --
http://firewall-jay.sourceforge.net/