The boot disks don't always work.  Some releases are just plain broken. 
I found one that worked and always used that.  If you still have your
old 1.2G boot floppy, boot off that... it's just as good.  You can try
to copy in the new miniroot if you want, but I can't even see any reason
why the old one couldn't be used to install the newer NetBSD. (except
that you'd have to make sure you install the new kernel)

I don't use boot disks any more.  I've figured out how to netboot a
MicroVAX II, and I do that... it's faster, a lot less trouble and it
actually *works*.  OTOH, setting it up can be a bit more confusing
because the netbsd boot program doesn't support qe so you need to use
etftp instead.

-- 
|  Boris Gjenero <bgjenero@undergrad.math.uwaterloo.ca>              |
|  Home page:  http://www.undergrad.math.uwaterloo.ca/~bgjenero/     |
|  "Luke, you're going to find that many of the truths we cling to   |
|  depend greatly on our own point of view." - Obi-Wan Kenobi, ROTJ  |