not able to upgrade from 13.10 to 14.04

[Bipin Bachhao]

trying to upgrade from 13.10 to 14.04

Ign http://in.archive.ubuntu.com trusty/main Translation-en_IN
Ign http://in.archive.ubuntu.com trusty/multiverse Translation-en_IN
Ign http://in.archive.ubuntu.com trusty/restricted Translation-en_IN
Ign http://in.archive.ubuntu.com trusty/universe Translation-en_IN
Fetched 29.1 MB in 6s (0 B/s)

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done
Building data structures... Done

Calculating the changes

Calculating the changes

Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade.

This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug using the
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
Building data structures... Done

root@xyz :~# lsb_release -rd
Description: Ubuntu 13.10
Release: 13.10

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: ubuntu-release-upgrader-core 1:0.205.5 [origin: unknown]
ProcVersionSignature: Ubuntu 3.11.0-20.34-generic 3.11.10.6
Uname: Linux 3.11.0-20-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
CrashDB: ubuntu
Date: Fri Apr 18 12:14:38 2014
InstallationDate: Installed on 2013-12-07 (131 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to saucy on 2014-04-18 (0 days ago)
VarLogDistupgradeAptlog: Log time: 2014-04-18 12:14:12.956004