can't install kubuntu-desktop message when upgrading 12.04 to 14.04

[Sergio Anefalos Pereira]

hit alt + F2 and entered kubuntu-devel-release-upgrade

a window pop-up: Upgrading Ubuntu to version 14.04

Preparing to Upgrade -> OK
Setting new software channels ->

a window pop-up
Can't install 'kubuntu-desktop'
It was impossible to install a required package. Please report this
as a bug using 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.
hit close

another window pop-up

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 report this bug using the command
'ubuntu-bug ubuntu-release-upgrader-core' in a terminal

then I hit Close and the program stopped

Description: Ubuntu 12.04.4 LTS
Release: 12.04
Package: update-manager1:0.156.14.13

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.13
ProcVersionSignature: Ubuntu 3.2.0-61.92-generic-pae 3.2.55
Uname: Linux 3.2.0-61-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
Date: Fri May 2 11:32:43 2014
GsettingsChanges:

InstallationMedia: Kubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=
 TERM=xterm
 PATH=(custom, no user)
 LANG=C
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-05-02 (0 days ago)
VarLogDistupgradeTermlog: