package isc-dhcp-client 4.2.4-7ubuntu12.3 failed to install/upgrade: unable to install (supposed) new info file `/var/lib/dpkg/tmp.ci/preinst': Is a directory

[francesco romeo]

 Preparativi per estrarre .../isc-dhcp-client_4.2.4-7ubuntu12.4_amd64.deb...
Estrazione di isc-dhcp-client (4.2.4-7ubuntu12.4) su (4.2.4-7ubuntu12.3)...
dpkg: errore nell'elaborare l'archivio /var/cache/apt/archives/isc-dhcp-client_4.2.4-7ubuntu12.4_amd64.deb (--unpack):
 impossibile installare il (supposto) nuovo file di informazioni "/var/lib/dpkg/tmp.ci/preinst": È una directory
Si sono verificati degli errori nell'elaborazione:
 /var/cache/apt/archives/isc-dhcp-client_4.2.4-7ubuntu12.4_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: isc-dhcp-client 4.2.4-7ubuntu12.3
ProcVersionSignature: Ubuntu 3.13.0-76.120-generic 3.13.11-ckt30
Uname: Linux 3.13.0-76-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
Date: Thu Jan 28 10:38:14 2016
DpkgTerminalLog:
 Preparing to unpack .../isc-dhcp-client_4.2.4-7ubuntu12.4_amd64.deb ...
 Unpacking isc-dhcp-client (4.2.4-7ubuntu12.4) over (4.2.4-7ubuntu12.3) ...
 dpkg: error processing archive /var/cache/apt/archives/isc-dhcp-client_4.2.4-7ubuntu12.4_amd64.deb (--unpack):
  unable to install (supposed) new info file `/var/lib/dpkg/tmp.ci/preinst': Is a directory
DuplicateSignature: package:isc-dhcp-client:4.2.4-7ubuntu12.3:unable to install (supposed) new info file `/var/lib/dpkg/tmp.ci/preinst': Is a directory
ErrorMessage: unable to install (supposed) new info file `/var/lib/dpkg/tmp.ci/preinst': Is a directory
InstallationDate: Installed on 2014-04-21 (646 days ago)
InstallationMedia: It
RelatedPackageVersions:
 dpkg 1.17.5ubuntu5.5
 apt 1.0.1ubuntu2.10
SourcePackage: isc-dhcp
Title: package isc-dhcp-client 4.2.4-7ubuntu12.3 failed to install/upgrade: unable to install (supposed) new info file `/var/lib/dpkg/tmp.ci/preinst': Is a directory
UpgradeStatus: No upgrade log present (probably fresh install)