I'm currently paused in the middle of running sysinst, upgrading 
a 2.02 system to 2.1, having just gotten the above warning.  The
machine is booted from the ISO CD referenced by the torrent file
linked under "NetBSD-2.1/i386" at
http://www.netbsd.org/mirrors/torrents/#2.1-ports

I was however not installing from CD but from a local mirror of
ftp.netbsd.org:/pub/NetBSD/NetBSD-2.1.  I suspect my problem 
is that that mirror is incomplete:  it contains only some of the
subdirectories of /pub/NetBSD/NetBSD-2.1:

drwxr-xr-x  4 root  wheel     512 Nov  5 14:12 i386/
drwxr-xr-x  3 root  wheel     512 Nov  5 14:52 shared/
drwxr-xr-x  3 root  wheel     512 Nov  5 14:28 source/

If I'm right about this, can somoene tell me what else I should
be mirroring.  If I am wrong, can you tell me what the right way
to fix this error is?

Thanks in advance,

---Alex