Downgrading a few testing packages on a stable system

["Rich Stanton" <rich@virology.uwcm.ac.uk>]

Hi,

I need some help sorting out a bit of a mess I've created.  I have a
stable (woody) system.  I use cups with gimpprint to print, and wanted a
driver for a newer printer which apparently is supported in newer versions
of gimpprint.  I therefore installed gimpprint from testing.  That went
fine, except when I try & add printers through the cups web interface,
after choosing the printer name I get a '404' error.  I therefore decided
to try & go back to my previous version of gimpprint.

Here's what apt did when I first installed the testing version of gimpprint:

debian:~# apt-get -t testing install cupsys-driver-gimpprint -u
Reading Package Lists... Done
Building Dependency Tree... Done
The following extra packages will be installed:
  libc6 libc6-dev libcupsimage2 libcupsys2 libdb1-compat libgcrypt1
  libgimpprint1 libgnutls7 liblzo1 libpng12-0 libtasn1-0 linux-kernel-headers
  locales zlib1g
The following packages will be REMOVED:
  libnss-db
The following NEW packages will be installed:
  libcupsimage2 libdb1-compat libgcrypt1 libgnutls7 liblzo1 libpng12-0
  libtasn1-0 linux-kernel-headers
The following packages will be upgraded
  cupsys-driver-gimpprint libc6 libc6-dev libcupsys2 libgimpprint1 locales
  zlib1g


In order to go back, I created the file /etc/apt/preferences and added the
following to it:
Package: *
Pin: release a=stable
Priority: 1001

I then ran apt-get update followed by apt-get upgrade but it didn't change
anything.  Removing gimpprint & installing the stable version fails with
broken dependencies relating to libc6.

Where do I go from here?