ipfilter error on 5.3

[dave]

Hello,
    I'm getting a strange startup error from ipfilter on system boot. This
is on a 5.3 box and happens whether i load ipfilter as a kld, i am not doing
this i've found that method relies on having ipv6 enabled which i don't
want, or loading it in to the kernel. I've added:
options IPFILTER
to the kernel, recompiled and rebooted. I then added:
ipfilter_enable="YES"
ipfilter_rules="/etc/ipf.rules"
and another reboot. Ipfilter starts logs, but immediately after i get
logging enabled i get this:
Enabling ipfilter.
ioctl(SIOCIPFL6): Invalid argument
Any suggestions? I don't know if this is a show stopper, if it's not
loading, but i'd like toknow what this error is and get rid of it if
possible.
Thanks.
Dave.