package python-apt 0.7.4ubuntu4 failed to install/upgrade: subprocess pre-installation script returned error exit status 1

Binary package hint: python-apt

$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=8.04
DISTRIB_CODENAME=hardy
DISTRIB_DESCRIPTION="Ubuntu hardy (development branch)"

$ dpkg -l python-apt
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Installed/Config-f/Unpacked/Failed-cfg/Half-inst/t-aWait/T-pend
|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
||/ Name Version Description
+++-==============-==============-============================================
ii python-apt 0.7.4ubuntu4 Python interface to libapt-pkg

On an updating process, it occured.

ProblemType: Package
Architecture: i386
Date: Tue Feb 19 07:23:08 2008
DistroRelease: Ubuntu 8.04
ErrorMessage: subprocess pre-installation script returned error exit status 1
Package: python-apt 0.7.4ubuntu4
PackageArchitecture: i386
SourcePackage: python-apt
Title: package python-apt 0.7.4ubuntu4 failed to install/upgrade: subprocess pre-installation script returned error exit status 1
Uname: Linux azure 2.6.24-8-generic #1 SMP Thu Feb 14 20:40:45 UTC 2008 i686 GNU/Linux