update manager fails due to bad header data

Message from Update manager....

Could not initialize the package information

An unresolvable problem occurred while initializing the package information.

Please report this bug against the 'update-manager' package and include the following error message:

'E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/de.archive.ubuntu.com_ubuntu_dists_precise-backports_main_binary-i386_Packages, E:The package lists or status file could not be parsed or opened.'

Working on 12.04LTS
32bit Pentium M 1GB

Followed a network download failure during package scan

Tried rebooting, no success