passive ftp clarification

This might be a duplicate post - I sent the first from the wrong email account.

Anyway,

I have this script below:

#!/bin/bash

#-------------------------------

# updated RC.FIREWALL script 
# with supposed FTP support? HELP!
#-------------------------------

# enable ip_forwarding
echo "1" > /proc/sys/net/ipv4/ip_forward

# added for Passive FTP Compatibility
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_nat_ftp

# Flush tables

iptables -F
iptables -t nat -F

# Set Default policies

iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT

iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT

BLOCKT="1:1024 5900 5900 2301 2381 3372 5000 1433 1801 2103:2105 3146" BLOCKU="1:1024 2301 2381 3372 1900 1434 3145 3527"

iptables -A INPUT -i eth0 -p tcp --dport 80 -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 110 -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 25 -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 443 -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 53 -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 20:22 -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 308 -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 90 -j ACCEPT

# BLOCK BAD TCP
for BT in $BLOCKT; do

        iptables -A INPUT -i eth0 -p tcp --dport $BT -j DROP;

done

# BLOCK BAD UDP
for BU in $BLOCKU; do

        iptables -A INPUT -i eth0 -p tcp --dport $BU -j DROP;

done

# END OF SCRIPT

It's pretty basic, and I know its not really too secure, but I am trying to narrow down this FTP passive problem.

I can login to passive FTP servers, but it hangs at 'ls'.

Is there something else in my script that I need to add to get ftp-data to respond correctly ?

Thanks in advance,

Chris