Networking :: Host Lists Of Ettercap Is Empty

My Host Lists of Ettercap is empty when I try to sniff my Lan. I modified /etc/etter.con, obtaining this:

Code:
# if you use iptables:
redir_command_on = "iptables -t nat -A PREROUTING -i %iface -p tcp --dport %port -j REDIRECT --to-port %rport"
redir_command_off = "iptables -t nat -D PREROUTING -i %iface -p tcp --dport %port -j REDIRECT --to-port %rport"
and the error is this:

Code: iptables v1.4.6: can't initialize iptables table `nat': Permission denied (you must be root)
Perhaps iptables or your kernel needs to be upgraded. I lunch ettercap as root.