Can't ping on Fedora 10 affer config NAT iptables

Currently,i use Fedora 10 and get a follow trouble :
My network:
route(10.11.10.2/24)----eth0----(10.11.10.105/24)Fedora10(172.16.239.1/24)----vmnet0----(172.16.239.2/24)Virtual Machine XP2.
I used : Vmware 6.5.1,Virtual Machine : Window XP SP2.
, iptable 1.4.1.1
I set up static ip on the machines:
Fedora:
NIC eth0: IP:10.11.10.105/24
GW:10.11.10.2
DNS:8.8.8.8
NIC vmnet0:
IP:172.16.239.1/24
On Fedora,i connected Internet ok !
Virtual machine XP:
NIC vmnet0:
IP:172.16.239.2/24
GW:172.16.239.1
DNS:8.8.8.8

Next,I have configured iptables as follows:
#delete all rules in nat,filter table
iptables --flush
iptables --table nat --flush
iptables --delete-chain
iptables --table nat --delete-chain
#build nat rules
iptables --table nat --append POSTROUTING --out-interface eth0 -j MASQUERADE
iptables --append FORWARD --in-interface vmnet0 -j ACCEPT
# Enables packet forwarding by kernel
echo 1 > /proc/sys/net/ipv4/ip_forward
# restart iptables
service iptables restart

Finally,I proceed test from Virtual machine :
ping 172.16.239.1 --->OK
ping 10.11.10.2 --->Request time out

Please helped me ! I have delayed here for a long time...
Thanks in advanced !

what is the output of

iptables -L

Thanks you !
I have solved it !
I missed command :

iptables --append FORWARD --in-interface eth0 -j ACCEPT