package proftpd 1.3.1-6ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

This error happened in the terminal window with the command of sudo apt-get install proftpd.

root@vamp-GA-870A-UD3:/home/vamp# sudo apt-get install proftpd
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
  linux-headers-3.5.0-17
Use 'apt-get autoremove' to remove it.
The following extra packages will be installed:
  libmysqlclient15off libpq5 libssl0.9.8
Suggested packages:
  proftpd-doc
The following NEW packages will be installed:
  libmysqlclient15off libpq5 libssl0.9.8 proftpd
0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
Need to get 3,830 kB of archives.
After this operation, 10.4 MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://us.archive.ubuntu.com/ubuntu/ quantal-updates/universe libssl0.9.8 amd64 0.9.8o-7ubuntu3.1 [861 kB]
Get:2 http://ubuntu.mirror.cambrium.nl/ubuntu/ hardy/main libmysqlclient15off amd64 5.0.51a-3ubuntu5 [1,877 kB]
Get:3 http://us.archive.ubuntu.com/ubuntu/ quantal-updates/main libpq5 amd64 9.1.6-1ubuntu1 [81.3 kB]
Get:4 http://ubuntu.mirror.cambrium.nl/ubuntu/ hardy/universe proftpd amd64 1.3.1-6ubuntu1 [1,010 kB]
Fetched 3,830 kB in 2s (1,277 kB/s)
Preconfiguring packages ...
Selecting previously unselected package libssl0.9.8:amd64.
(Reading database ... 186968 files and directories currently installed.)
Unpacking libssl0.9.8:amd64 (from .../libssl0.9.8_0.9.8o-7ubuntu3.1_amd64.deb) ...
Selecting previously unselected package libmysqlclient15off.
Unpacking libmysqlclient15off (from .../libmysqlclient15off_5.0.51a-3ubuntu5_amd64.deb) ...
Selecting previously unselected package libpq5.
Unpacking libpq5 (from .../libpq5_9.1.6-1ubuntu1_amd64.deb) ...
Selecting previously unselected package proftpd.
Unpacking proftpd (from .../proftpd_1.3.1-6ubuntu1_amd64.deb) ...
Processing triggers for ureadahead ...
Processing triggers for man-db ...
Setting up libssl0.9.8:amd64 (0.9.8o-7ubuntu3.1) ...
Setting up libmysqlclient15off (5.0.51a-3ubuntu5) ...
Setting up libpq5 (9.1.6-1ubuntu1) ...
Setting up proftpd (1.3.1-6ubuntu1) ...
Installing new version of config file /etc/init.d/proftpd ...
Installing new version of config file /etc/default/proftpd ...
grep: /etc/inetd.conf: No such file or directory
 * Starting ftp server proftpd - mod_tls/2.1.2: compiled using OpenSSL version 'OpenSSL 0.9.8g 19 Oct 2007' headers, but linked to OpenSSL version 'OpenSSL 0.9.8o 01 Jun 2010' library
 - Fatal: LoadModule: error loading module 'mod_dynmasq.c': Permission denied on line 73 of '/etc/proftpd/modules.conf'
                                                                                                                [fail]
invoke-rc.d: initscript proftpd, action "start" failed.
dpkg: error processing proftpd (--configure):
 subprocess installed post-installation script returned error exit status 1
W: Duplicate sources.list entry http://archive.canonical.com/ubuntu/ quantal/partner amd64 Packages (/var/lib/apt/lists/archive.canonical.com_ubuntu_dists_quantal_partner_binary-amd64_Packages)
W: Duplicate sources.list entry http://archive.canonical.com/ubuntu/ quantal/partner i386 Packages (/var/lib/apt/lists/archive.canonical.com_ubuntu_dists_quantal_partner_binary-i386_Packages)
W: You may want to run apt-get update to correct these problems
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 12.10
Package: proftpd 1.3.1-6ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-19.30-generic 3.5.7
Uname: Linux 3.5.0-19-generic x86_64
ApportVersion: 2.6.1-0ubuntu9
Architecture: amd64
Date: Mon Dec 17 15:18:11 2012
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2012-12-12 (5 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
SourcePackage: proftpd-dfsg
Title: package proftpd 1.3.1-6ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)