package libnm-glib-vpn1:amd64 1.2.6-0ubuntu0.16.04.1 failed to install/upgrade: package is in a very bad inconsistent state; you should reinstall it before attempting configuration

[Amit Ashok]

i was trying to install a software dia from https://sourceforge.net/projects/dia-installer/?source=typ_redirect when i came across this issue

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: libnm-glib-vpn1:amd64 1.2.6-0ubuntu0.16.04.1
ProcVersionSignature: Ubuntu 4.4.0-78.99-generic 4.4.62
Uname: Linux 4.4.0-78-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
Date: Thu Jun 15 09:43:23 2017
DuplicateSignature:
 package:libnm-glib-vpn1:amd64:1.2.6-0ubuntu0.16.04.1
 Processing triggers for fontconfig (2.11.94-0ubuntu1.1) ...
 dpkg: error processing package libnm-glib-vpn1:amd64 (--configure):
  package is in a very bad inconsistent state; you should
ErrorMessage: package is in a very bad inconsistent state; you should reinstall it before attempting configuration
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2016-06-17 (362 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
IpRoute:
 default via 192.168.1.1 dev wlan0 proto static metric 600
 169.254.0.0/16 dev wlan0 scope link metric 1000
 192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.7 metric 600
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.2
 apt 1.2.20
SourcePackage: network-manager
Title: package libnm-glib-vpn1:amd64 1.2.6-0ubuntu0.16.04.1 failed to install/upgrade: package is in a very bad inconsistent state; you should reinstall it before attempting configuration
UpgradeStatus: Upgraded to xenial on 2016-08-01 (317 days ago)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 wlan0 wifi connected /org/freedesktop/NetworkManager/Devices/0 DNA-A213 6036aba9-f380-4b67-9382-b8ebbb6ecd8e /org/freedesktop/NetworkManager/ActiveConnection/2
 eth0 ethernet unavailable /org/freedesktop/NetworkManager/Devices/1 -- -- --
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/2 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.2.6 connected started full enabled enabled enabled enabled enabled