Comment 40 for bug 201673

Not 100% sure this is related. I'm running Hardy Alpha 64-bit, not because I am experienced, but because it has the drivers necessary for my wi-fi that Gutsy lacked.

Very successful until recent upgrade which failed to complete. The system is still booting and working fine but it impossible to do any installs/updates/upgrades.

Adept Updater simply reports
There was an error commiting changes. Possibly there was a problem downloading some packages or the commit would break packages.

Synaptic finds two broken packages: libc6-dev and libc6-i386, claims to successfully fix the dependency problems, but clearly doesn't!

libc6 is marked for upgrade from 2.7-5ubuntu2 to 2.7-9ubuntu2 but the upgrade fails and cannot be "unmarked".

Report from applying the upgrade is:
E: /var/cache/apt/archives/libc6_2.7-9ubuntu2_amd64.deb: subprocess pre-installation script returned error exit status 1

sudo apt-get -f upgrade gives (install gives similar):

Preparing to replace libc6 2.7-5ubuntu2 (using .../libc6_2.7-9ubuntu2_amd64.deb) ...
debconf: DbDriver "config": could not open /var/cache/debconf/config.dat
dpkg: error processing /var/cache/apt/archives/libc6_2.7-9ubuntu2_amd64.deb (--unpack):
 subprocess pre-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/libc6_2.7-9ubuntu2_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Any help appreciated, I do realise that Alpha versions carry risks, so will live with it if I have to.