package mantis 1.2.10-1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[sri]

package mantis 1.2.10-1 failed to install

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: mantis 1.2.10-1
ProcVersionSignature: Ubuntu 3.2.0-27.43-generic 3.2.21
Uname: Linux 3.2.0-27-generic x86_64
ApportVersion: 2.0.1-0ubuntu12
AptOrdering:
 mantis: Install
 mantis: Configure
Architecture: amd64
Date: Sat Aug 18 17:00:41 2012
DuplicateSignature:
 Setting up mantis (1.2.10-1) ...
 Not replacing deleted config file /etc/mantis/apache.conf
 chmod: cannot access `/etc/mantis/apache.conf': No such file or directory
 dpkg: error processing mantis (--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" - Release amd64 (20110427.1)
PackageArchitecture: all
SourcePackage: mantis
Title: package mantis 1.2.10-1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to precise on 2012-08-04 (15 days ago)
modified.conffile..etc.mantis.apache.conf: [deleted]

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.