LinuxQuestions.org - Iptables, invalid argument, problem with modprobe

I want to lock certain IP to a MAC address and I tried that:
iptables -t nat -A POSTROUTING -s 1.2.3.4 -m mac --mac-source aa:bb:cc:dd -j SNAT --to-source 192.168.1.2
iptables -t nat -A POSTROUTING -s 1.2.3.4 -j DROP
But after the first line I got:
iptables: Invalid argument
Here is what I got from lsmod (hm.. I know mac match support is compiled into the kernel):

Code:

Module                  Size  Used by    Not tainted

ipt_REDIRECT            696  1  (autoclean)

8139too                16040  2 

mii                    2368  0  [8139too]

And here is what locate gave me:

Code:

# locate ipt |grep mac

/lib/modules/2.4.20/kernel/net/ipv4/netfilter/ipt_mac.o.gz

/usr/lib/iptables/libip6t_mac.so

/usr/lib/iptables/libipt_mac.so

/usr/src/linux-2.4.22/net/ipv4/netfilter/ipt_mac.c

/usr/src/linux-2.4.22/include/linux/netfilter_ipv4/ipt_mac.h

/usr/local/lib/iptables/libip6t_mac.so

/usr/local/lib/iptables/libipt_mac.so

/usr/local/src/libpng/scripts/makefile.macosx

/usr/include/linux/netfilter_ipv4/ipt_mac.h

I tried to load a module:
modprobe libipt_mac
modprobe ipt_mac
, but always got modprobe: Can't locate module...
And one more thing: I'm using source-compiled version of iptables: v1.3.0rc1
Where could be the problem in that setup?