Unable to upgrade to 15.04

[Moroine]

I was on 14.04 I frist launch do-release-upgrade this resulting to upgrading to 14.10 according to actual system details panel (About this computer page).

Then I try to launch again to upgrade to 15.04 but the problem appears

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: ubuntu-release-upgrader-core 1:14.10.10
ProcVersionSignature: Ubuntu 3.16.0-41.57-generic 3.16.7-ckt11
Uname: Linux 3.16.0-41-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.14.7-0ubuntu8.5
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Mon Jun 29 22:44:15 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-10-10 (262 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to utopic on 2015-06-29 (0 days ago)

[Brian Murray (brian-murray)]

Reviewing the files from your upgrade attempt you seem to have enabled a PPA that provides Xorg packages. This will prevent the upgrade as that PPA contains different versions of packages essential to Ubuntu. The page, https://launchpad.net/~xorg-edgers/+archive/ppa, contains details on to how to revert to the official Xorg packages for the xorg-edgers PPA. Instructions for reverting to official Xorg packages should be similar for the PPA that you have enabled.