Cannot upgrade from 11.04 to 11.10

[Septic80]

Upgrade halts saying that broken packages held. Have tried to sort this on synaptic package manager, but no broken packages found.
Upgrade cancels then reverts to last system setup.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: update-manager 1:0.150.5.4
ProcVersionSignature: Ubuntu 2.6.38-15.61-generic 2.6.38.8
Uname: Linux 2.6.38-15-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Sat Jul 7 09:24:51 2012
GConfNonDefault:
 /apps/update-manager/check_new_release_ignore=
 /apps/update-manager/first_run=false
 /apps/update-manager/show_details=true
 /apps/update-manager/window_size=(500,524)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to natty on 2012-07-07 (0 days ago)
VarLogDistupgradeApttermlog:

VarLogDistupgradeHistorylog:

VarLogDistupgradeTermlog:

[dino99 (9d9)]

That version is no more maintained