package apt 0.8.16~exp5ubuntu13.7 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Eric Weidner]

Trying to get from 11.04 to 12.04.

- Replaced 11.04 sources list with old-releases repos.
- Added to keyring
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 437D05B5 3E5C1192
- do-release-upgrade

Finally starts working to go to 11.10 but fails with the following error.

Setting up apt (0.8.16~exp5ubuntu13.7) ...
Installing new version of config file /etc/cron.daily/apt ...
Installing new version of config file /etc/apt/apt.conf.d/20changelog ...
ERROR: Can't find the archive-keyring
Is the ubuntu-keyring package installed?
dpkg: error processing apt (--configure):
 subprocess installed post-installation script returned error exit status 1
Exception during pm.DoInstall(): E:Sub-process /usr/bin/dpkg returned an error code (1)

*** The package "apt 0.8.16~exp5ubuntu13.7" failed to install or upgrade.

ProblemType: Package
DistroRelease: Ubuntu 11.10
Package: apt 0.8.16~exp5ubuntu13.7
ProcVersionSignature: Ubuntu 2.6.38-8.42-virtual 2.6.38.2
Uname: Linux 2.6.38-8-virtual x86_64
Architecture: amd64
Date: Thu Jul 11 17:42:28 2013
Ec2AMI: ami-409e4c29
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: us-east-1b
Ec2InstanceType: m1.small
Ec2Kernel: aki-427d952b
Ec2Ramdisk: unavailable
ErrorMessage: subprocess installed post-installation script returned error exit status 1
SourcePackage: apt
Title: package apt 0.8.16~exp5ubuntu13.7 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to oneiric on 2013-07-11 (0 days ago)

[dino99 (9d9)]

Oneiric is no more maintained since a while, and such issue is not met with recent package