[squid-users] iptables stops pingning

Hello,
           I am using SQUID 2.6.STABLE17 with fedora core 8, & BIND
DNS SERVER configured on the same box, i have configured squid as
transparent proxy, and applied iptables rule by using the following
command

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT
--to-port 3128

service iptables save

          so when i restart iptables after appling & saving above i
get following:

Flushing firewall rules: [ OK ]
Setting chains to policy ACCEPT: filter nat [ OK ]
Unloading iptables modules: [FAILED]
Applying iptables firewall rules: [ OK ]
Loading additional iptables modules: nf_conntrack_netbios_n[ OK ]

          so if i try to ping to (any public ip) from client PC after
enabling iptables i get request time out, but i can browse websites
without any problem, and if i disable iptables i can get reply from
the (public ip) to which i am pinging and browsing also works. also
checked DNS resolution it works perfectly as browsing works.

          so i would like to know what is the reason of stopping ping
after enabling iptables and why i am getting Unloading iptables
modules FAILED.

          for reference i have attached my iptables & squid.conf file,
PLZ HELP ME OUT.

THANKS IN ADVANCE

-- 
Regards,
Yogesh Patil