Can't purge wireshark (" $ sudo aptitude --purge-unused purge wireshark ")

Binary package hint: wireshark

$ sudo aptitude --purge-unused purge wireshark-common
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
The following packages will be REMOVED:
  wireshark-common{p}
0 packages upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.
Do you want to continue? [Y/n/?]
Writing extended state information... Done
(Reading database ... 235350 files and directories currently installed.)
Removing wireshark-common ...
Purging configuration files for wireshark-common ...
The group `wireshark' is not a system group. Exiting.
dpkg: error processing wireshark-common (--purge):
 subprocess installed post-removal script returned error exit status 3
Errors were encountered while processing:
 wireshark-common
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done

$ lsb_release -rd
Description: Ubuntu 9.10
Release: 9.10

$ apt-cache policy wireshark
wireshark:
  Installed: (none)
  Candidate: 1.2.2-2
  Version table:
     1.2.2-2 0
        500 file: karmic/universe Packages

$ apt-cache policy wireshark-common
wireshark-common:
  Installed: (none)
  Candidate: 1.2.2-2
  Version table:
     1.2.2-2 0
        500 file: karmic/universe Packages
        100 /var/lib/dpkg/status

"wireshark" package gets purged, but "wireshark-common" keeps throwing errors

ProblemType: Package
AptOrdering:
 wireshark: Purge
 wireshark-common: Purge
 libc-ares2: Purge
 libsmi2-common: Purge
 libsmi2ldbl: Purge
Architecture: i386
Date: Mon Mar 1 20:56:07 2010
DistroRelease: Ubuntu 9.10
ErrorMessage: subprocess installed post-removal script returned error exit status 3
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
NonfreeKernelModules: hsfengine wl
Package: wireshark-common (not installed)
ProcVersionSignature: Ubuntu 2.6.31-17.54-generic
SourcePackage: wireshark
Title: package wireshark-common (not installed) failed to install/upgrade: subprocess installed post-removal script returned error exit status 3
Uname: Linux 2.6.31-17-generic i686