[CentOS] Iptables port forwarding help

Hello,

I have a webcam that I wish to view from the internet. It is a wireless linksys model with an ip address of 192.168.1.15. I have it set on port 8081, 192.168.1.15:8081.

I am using the IP Masquerade HowTo script. Here's the rule I added to my firewall script:

EXTIF="ppp0" INTIF="eth1" EXTIP="`$IFCONFIG $EXTIF | grep inet | cut -d : -f 2 | cut -d \ -f 1`"

$IPTABLES -A FORWARD -i $EXTIF -o $INTIF -p tcp --dport 8081 -m state \ --state NEW,ESTABLISHED,RELATED -j ACCEPT

$IPTABLES -A PREROUTING -t nat -p tcp -d $EXTIP --dport 8081 \ -j DNAT --to 192.168.1.15:8081

Its not working. Can anyone offer a suggestion?

TIA