booting ibm pps 830.

i have a 'supposed to be working' mainboard from ibm personal power system
830.  it does not have parity memory and cache module.  after connecting
everything, it boots into SMS and passes all the tests.  however,
for some reason, it's unable to boot netbsd.  i downloaded netbsd-1.6.1/prep
and tried to boot from cd.  the machine completely ignored me.  i guess
either the cd is not bootable, or pps needs drive supporting 512B sectors.
then i tried booting from floppies.  every one of them hang pps, clearing
the lowest ~seven lines of text with white space.  then, i tried dd'ing
floppy images onto hard disk.  the result was the same.  any idea what
might be wrong?