panic: npxdna vector not initialized

[elliot d schlegelmilch <elliot_(_at_)_cs_(_dot_)_montana_(_dot_)_edu>]

This is my first post, so I'll try to be as concise as possible.
I was running an older version of FreeBSD (4.6?), but wanted to switch 
to OpenBSD on this 486 I have to build a filtering bridge. After 
discovering that OpenBSD required more than 16MB of ram, I put some more 
ram in the box and I came across the following issue:

This happens right after the line "starting network":

panic: npxdna vector not initialized
Stopped at Debugger+0x4: leave
ddb> ps
PID	PPID	PGRP	UID	S	FLAGS	WAIT	COMMAND
26221	8219	8219	0	2	0x4006			dd
8219	1	9219	0	3	0x4086	 pause		sh
7	0	0	0	3	0x100204 crypto_wa	crypto
6	0	0	0	3	0x100204 aiodoned	aiodoned
5	0	0	0	3	0x100304 syncer		update
4	0	0	0	3	0x100204 cleaner	cleaner
3	0	0	0	3	0x100204 reaper		reaper
2	0	0	0	3	0x100204 pgdaemon	pagedaemon
1	0	1	0	3	0x4084	 wait		init
0	-1	0	0	3	0x80204	 scheduler	swapper

ddb> trace
Debugger(cfbf0d2c, 7c5c500. 7c5c500c, d05605a0,0) at Debugger+0x4
panic(d0532364,400,3,2,0) at panic+0x87
clock_secs_to_ymdhms(d3e14a00) at clock_secs_to_ymdhms+0x227

I searched Google for this problem, and came up with only two remotely 
close references:

http://groups.google.com/groups?q=npxdna+bug&hl=en&lr=&ie=UTF-8&c2coff=1&safe=off&selm=200203070818.g278I8q18526%40chiharu.homeip.net&rnum=3
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&c2coff=1&safe=off&threadm=b0j2vt%242t5s%241%40FreeBSD.csie.NCTU.edu.tw&rnum=1&prev=/groups%3Fq%3Dnpxdna%2Bopenbsd%26hl%3Den%26lr%3D%26ie%3DUTF-8%26c2coff%3D1%26safe%3Doff%26selm%3Db0j2vt%25242t5s%25241%2540FreeBSD.csie.NCTU.edu.tw%26rnum%3D1


It may also be worth noting that neither FreeBSD 4.10 nor 5.2.1 boot on 
this machine either. With 5.x /bin/sh cores in signal 8, but 4.10 I 
believe is a mysterious npx panic as well.