Help on NetMeeting over iptable

Dear All

I have problem in enabling netmeeting over a RH9 linux firewell
running iptable.

I have patched the kernel and set the port forwarding rules in the
firewell script.

When I use 'lsmod' have the following result :

<================================================= ==========>
ipt_REJECT 3928 4 (autoclean)
ipt_unclean 8024 2 (autoclean)
ipt_LOG 4184 5 (autoclean)
ipt_state 1080 110 (autoclean)
iptable_mangle 2776 0 (autoclean) (unused)
iptable_filter 2412 1 (autoclean)
ip_conntrack_h323 3424 1 (autoclean)
ip_nat_h323 3356 0 (unused)
ip_conntrack_ftp 5296 1 (autoclean)
ip_nat_ftp 4112 0 (unused)
iptable_nat 21720 3 [ip_nat_h323 ip_nat_ftp]
ip_tables 15096 9 [ipt_REJECT ipt_unclean ipt_LOG
ipt_state iptable_mangle iptable_filter iptable_nat]
ip_conntrack 26976 4 [ipt_state ip_conntrack_h323
ip_nat_h323 ip_conntrack_ftp ip_nat_ftp iptable_nat]
autofs 13268 0 (autoclean) (unused)
3c59x 30704 2
ext3 70784 2
jbd 51892 2 [ext3]
<================================================= ==========>

and the firewell script is like that :

<================================================= ==========>
# Add NetMeeting Support one-to-one IP Mapping
H323_PORTS="389 522 1503 1720 1731 8080"
HI_PORTS="1024:65535"

if [ -e $IPMap ]; then
DST_PORTS=`echo $HI_PORTS|tr : -`

ip_map=`grep -v ^# $IPMap`

for i in $ip_map; do
ip_src=`echo $i|cut -d: -f1`
ip_des=`echo $i|cut -d: -f2`

for PORT in $H323_PORTS; do
iptables -t nat -A PREROUTING -i $EXTERNALIF -p tcp -d $ip_src
--dport $PORT -m state --state
NEW,ESTABLISHED,RELATED -j DNAT --to-destination $ip_des:$PORT
done

# iptables -t nat -A PREROUTING -i $EXTERNALIF -p udp -d $ip_src
--dport $HI_PORTS -m state --sta
te ESTABLISHED,RELATED -j DNAT --to-destination $ip_des:$HI_PORTS
iptables -t nat -A PREROUTING -i $EXTERNALIF -p udp -d $ip_src
--dport $HI_PORTS -m state --stat
e ESTABLISHED,RELATED -j DNAT --to-destination $ip_des:$DST_PORTS
done
fi
<================================================= ==========>

that script can work at the begining but
I cannot connect to the internal PC with its related true IP
from external

I have search over the news group but did not find any case like that

Could anyone give me an help hand or point me a right direction?

Thanks a lot
Eric