package libqalculate4 0.9.6-3ubuntu1 failed to install/upgrade: subprocess installed post-removal script returned error exit status 2

[join.doe]

uname -a: Linux toshuntu 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 16:20:31 UTC 2009 i686 GNU/Linux
l
sb_release -rd:
   Description: Ubuntu 9.10
   Release: 9.10

I was in the process of install ubuntu-edu-primary or preschoo, when my computer had its power taken away.
When restarted and tried to finish the install of the education suite Software Center reported errors saying that i couldn't install them - although it also showed them as being installed.

I tried removing and purging the offending packages with apt-get, aptitude and dpkg without luck.
There are apparently some dependices and configuration script that where intterupted under the initial install of education suite the packages that spring to mind are marble, step, ttf-bengali-fonts and libqalculate4 plus a handful of others.

I manage to remove all the offending applications except ttf-bengali-fonts. This package is stubborn and not allowing me to remove/purge it:

sudo dpkg --purge ttf-bengali-fonts:

(Reading database ... 152852 files and directories currently installed.)
Removing ttf-bengali-fonts ...
dpkg (subprocess): unable to execute installed pre-removal script: Exec format error
dpkg: error processing ttf-bengali-fonts (--purge):
 subprocess installed pre-removal script returned error exit status 2
dpkg (subprocess): unable to execute installed post-installation script: Exec format error
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 ttf-bengali-fonts

So that's where I stand. Hope this helps.

ProblemType: Package
AptOrdering:
 step: Remove
 libqalculate4: Remove
 libcln5: Remove
 ttf-bengali-fonts: Configure
Architecture: i386
Date: Tue Jan 12 22:05:42 2010
DistroRelease: Ubuntu 9.10
ErrorMessage: subprocess installed post-removal script returned error exit status 2
NonfreeKernelModules: nvidia
Package: libqalculate4 0.9.6-3ubuntu1
ProcVersionSignature: Ubuntu 2.6.31-17.54-generic
SourcePackage: libqalculate
Title: package libqalculate4 0.9.6-3ubuntu1 failed to install/upgrade: subprocess installed post-removal script returned error exit status 2
Uname: Linux 2.6.31-17-generic i686

[Jean-Baptiste Lallement (jibel)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that there was an error caused by a corrupted archive.
The corrupted packages are:
libqalculate4
libcln5
libmarble4
ttf-bengali-fonts

Please execute the following commands, in a terminal ( Applications -> Accessories -> Terminal ) :

sudo rm /var/lib/dpkg/info/{libqalculate4,libcln5,libmarble4,ttf-bengali-fonts}.{postinst,prerm,postrm}
sudo apt-get remove --purge libqalculate4 libcln5 libmarble4 ttf-bengali-fonts
sudo apt-get clean
sudo apt-get update

Then try performing the update again. This will likely resolve your issue. If so please set the bug's status to Invalid. Thanks in advance!

[join.doe (join-doe)]

Hi, I know I shouldn't comment her but I don't know how to set the bugs status to 'Invalid'.
Jean-Baptistes solution worked:
(Jean-Baptiste Lallement wrote on 2010-01-13: )

sudo rm /var/lib/dpkg/info/{libqalculate4,libcln5,libmarble4,ttf-bengali-fonts}.{postinst,prerm,postrm}
sudo apt-get remove --purge libqalculate4 libcln5 libmarble4 ttf-bengali-fonts
sudo apt-get clean
sudo apt-get update