>> It should "Just Work(tm)".  What did you use to write the disklabel?
>
> I used my NT system to write it to a dos partition then dded it to 
> /dev/sda via a Linux boot floppy.

You apprently failed to make correct NetBSD/pmax bootblock in your
disks.

As Simon points, go netboot-then-take standard installation way, or dd'ing
diskimage on the target disk.

Tohru Nishimura
Nara Institute of Science and Technology