[CentOS] Problems with 'iptables'

Hello!

Sorry if this question is already asked, but I not finding answer for it...
I have server with CentOS 6.4, later it will be router for home network.

When I tried tune iptables I have error:
 [root at gateway sysconfig]# iptables -t NAT -A POSTROUTING -o eth0 -j
MASQUERADE
 iptables v1.4.7: can't initialize iptables table `NAT': Table does not
exist (do you need to insmod?)
 Perhaps iptables or your kernel needs to be upgraded.

iptables 1.4.7 (latest version), custom kernel 3.8.3. from kernel.org (too
latest version)

How to fix this error, it's desirable without rebuild kernel?