iptables ULOG target gives "Invalid argument"

Binary package hint: iptables

thorin:~# iptables -A INPUT -j ULOG
iptables: Invalid argument
thorin:~# lsmod | egrep ^ip
ipt_ULOG 10632 1
ipv6 293768 28
ipt_state 2496 1
ip_conntrack 62724 1 ipt_state
iptable_filter 3648 1
ip_tables 21760 3 ipt_ULOG,ipt_state,iptable_filter
thorin:~# uname -a
Linux thorin 2.6.15-26-sparc64 #1 Fri Sep 8 19:56:21 UTC 2006 sparc64 GNU/Linux
thorin:~# dpkg --list iptables
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Installed/Config-files/Unpacked/Failed-config/Half-installed
|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
||/ Name Version Description
+++-==============-==============-============================================
ii iptables 1.3.3-2ubuntu4 Linux kernel 2.4+ iptables administration to

This is on 6.06 LTS.

A bit of looking around shows it's probably related to running a 32-bit userland with a 64-bit kernel. See Debian bug #232401. Either way, it's rather disturbing to find that I now have a production server without a sensible means of logging firewall actions :-(