upgrade proces 12.04 to 14.04 stops with error

[filu]

Error during upgrading 12.04LTS -> 14.04LTS

/var/log/dist-upgrade# cat main.log | grep -2 ERROR
2014-05-01 15:49:20,219 INFO apt version: '0.8.16~exp12ubuntu10.16'
2014-05-01 15:49:20,219 INFO release-upgrader version '0.220.2' started
2014-05-01 15:49:20,545 ERROR Could not find any typelib for WebKit
2014-05-01 15:49:20,545 ERROR html widget
Traceback (most recent call last):
  File "/tmp/update-manager-jEmJyo/DistUpgrade/DistUpgradeViewGtk3.py", line 435, in __init__
--
2014-05-01 15:50:03,337 DEBUG /openCache(), new cache size 45707
2014-05-01 15:50:03,337 DEBUG need_server_mode(): run in 'desktop' mode, (because of key deps for 'kubuntu-desktop')
2014-05-01 15:50:21,961 ERROR Dist-upgrade failed: 'E:Błąd, pkgProblemResolver::Resolve zwrócił błąd, może to być spowodowane zatrzymanymi pakietami.'
2014-05-01 15:50:21,978 DEBUG abort called
2014-05-01 15:50:21,981 DEBUG openCache()

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.13
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic 3.2.24
Uname: Linux 3.2.0-29-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
Date: Thu May 1 15:50:36 2014
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=
 TERM=xterm
 PATH=(custom, no user)
 LANG=pl_PL.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-05-01 (0 days ago)
VarLogDistupgradeTermlog: