killing the update and installation processes

while installing any package...giving the error below :-

The hostname -f command returned: $1

Your system needs to have a fully qualified domain name (fqdn) in
order to install the var-qmail packages.

Installation aborted.

dpkg: error processing qmail (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of qmail-run:
 qmail-run depends on qmail (>= 1.06-2.1); however:
  Package qmail is not configured yet.
dpkg: error processing qmail-run (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          Errors were encountered while processing:
 qmail
 qmail-run
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: qmail 1.06-4
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
ApportVersion: 2.0.1-0ubuntu5
Architecture: amd64
Date: Tue Aug 7 09:55:12 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
ProcEnviron:
 LANGUAGE=en_IN:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_IN
 SHELL=/bin/bash
SourcePackage: netqmail
UpgradeStatus: No upgrade log present (probably fresh install)