I've been seeing this same problem, (which, btw, gives me the same 
error message as when I was getting conflict with both console and
tty00 turned on with serial console/modem port enabled in the booter,
leading me to believe that it may be some sort of contention for a
device, whch i'd guess is the HD) ever since I moved my NetBSD root
to my external SCSI drive. I'm properly terminated, and have what
looks to me to be a high-quality SCSI cable (6 ft.), so I doubt
it's a bus issue, although it could be. (The internal hd, and my
external are the only two devices on the bus.)

I plan to re-install NetBSD on my internal drive (i am going to try
to do a recursive copy from my installed system rather than reinstall
from the tarballs), and I'll let you know if the error goes away.

My external hd is substantially faster than my internal, I dunno if
this has anything to do with it.

Also, i'm consistently unable to get the documentation to make;
comp10 is fully installed, along with misc, text, man, and all the 
other tarballs on cray-ymp.. I get errors from ld.so, I'll try and
post more specific errors in a little while.. it's a little bit
difficult for me to do so because I still haven't been able to get
cu to work (although i've only tried a little bit). anyone want
to tell me how I should setup my ttys file and the device permissions
to get cu to let me talk at my printer port? 

(Sorry for the multiple issues all at once and in the same messaghe,
i've been rather busy the past little bit..)