Bug#703404: Also encountered this during a testing netinstall.

[Karl Fogel <kfogel@red-bean.com>]

I ran into this problem too.  I was doing a netinstall of Debian
'testing' (having booted from a USB stick created by "zcat boot.img.gz >
/dev/sdb", then mounting, then running unetbootin on the same stick).

Early in the "Install the base system" stage, using the text (ncurses?
non-graphical, anyway) installer, my screen went red and the dialog box
showed this error:

  |                    Unable to install busybox
  |
  | An error was returned while trying to install the busybox package
  | onto the target system.
  |
  | Check /var/log/syslog or see virtual console 4 for details.
  |
  | <Go Back>                                      <Continue>

I looked on virtual console 4, and as expected, it got an error while
trying to install the busybox package:

  WARNING: The following packages cannot be authneticated!
      busybox
  E: There are problems and -y was used without --force-yes
  base-installer: error: \
  exiting on error base-installer/kernel/failed-package-install

I don't want to just force it through by ignoring the bad signature, as
I thought the whole point of the signature system is that something
might be wrong (e.g., in the worst case, that some third party has
tampered with the busybox package).  When a sig fails, what's the
standard procedure by the package maintainers?

[I don't quite understand the solutions others in this thread used.  For
example Tycho Lürsen said "I finaly have a working system, but I had to
switch mirrors twice during installation.  After the reboot, I still
could not use my system. I had to remove 'debian-archive-keyring' (witch
is not allowed unless you force it to) and replace it with the proper
one, reinstall apt, etc."  Not sure what he meant by "replace it with
the proper one", though.]

I'm happy to provide more info if it'll help solve this, but suspect
my report is just a "me too".

-Karl