can not calculate the size of upgreade, the essential package "ubuntu-minimal" could not be located

[bryan]

as i have been trying to up grade to any newer version it tells me the same errors no matter how i try to download and install mainly that it cant calculate the size of the package

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.13.0-72.115-generic 3.13.11-ckt30
Uname: Linux 3.13.0-72-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.8
Architecture: amd64
CrashDB: ubuntu
Date: Sat Dec 12 04:35:24 2015
InstallationDate: Installed on 2015-11-21 (20 days ago)
InstallationMedia: It
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to vivid on 2015-12-11 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2015-12-12 04:17:38.801604
 Log time: 2015-12-12 04:18:49.313918
 Log time: 2015-12-12 04:33:35.565474
 Log time: 2015-12-12 04:36:32.298409
VarLogDistupgradeTermlog:

mtime.conffile..etc.update.manager.release.upgrades: 2015-12-11T14:32:47.956909