package apport 1.20.1-0ubuntu5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

Binary package hint: apport

1) $ lsb_release -rd
Description: Ubuntu Natty (development branch)
Release: 11.04

2) $ apt-cache policy apport
apport:
  Installed: 1.20.1-0ubuntu5
  Candidate: 1.20.1-0ubuntu5
  Version table:
 *** 1.20.1-0ubuntu5 0
        500 http://us.archive.ubuntu.com/ubuntu/ natty/main i386 Packages
        100 /var/lib/dpkg/status

3) Expected the Update Manager to download and install latest development packages and install them.

4) Restarted system as requested by the Upgrade Manager, and got a dialog asking if I wanted to report the problem...

ProblemType: Package
DistroRelease: Ubuntu 11.04
Package: apport 1.20.1-0ubuntu5
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: nvidia
ApportLog:

AptOrdering:
 apport: Configure
 apport-gtk: Configure
Architecture: i386
CrashReports:
 600:1001:1001:16144034:2011-04-18 23:01:16.064290649 -0400:2011-04-18 23:00:33.156460557 -0400:/var/crash/_usr_bin_mythfrontend.real.1001.crash
 600:1001:1001:10214510:2011-04-18 20:34:09.464017000 -0400:2011-04-18 20:34:14.932022037 -0400:/var/crash/_usr_bin_compiz.1001.crash
 600:1000:1000:1064861:2011-04-17 17:39:38.236681000 -0400:2011-04-17 21:52:50.547463340 -0400:/var/crash/_usr_lib_policykit-1-gnome_polkit-gnome-authentication-agent-1.1000.crash
 600:0:0:681590:2011-04-20 22:26:10.554306000 -0400:2011-04-21 19:51:28.517899521 -0400:/var/crash/apport.0.crash
Date: Wed Apr 20 22:26:10 2011
DpkgTerminalLog:
 Setting up apport (1.20.1-0ubuntu4) ...
 start: Job failed to start
 invoke-rc.d: initscript apport, action "start" failed.
 dpkg: error processing apport (--configure):
  subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110301.7)
PackageArchitecture: all
SourcePackage: apport
Title: package apport 1.20.1-0ubuntu5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to natty on 2011-04-17 (4 days ago)