Installing (x)Ubuntu on my dated Toshiba Satellite everything went smooth. Just after finishing the installation and getting the first package updates a strange Error with system-tools-backends occured.

Luckily this problem is already known and a Workaround to fix this problem exists.

Open up a terminal and type the following:

sudo invoke-rc.d system-tools-backends stop

sudo dpkg –configure -a

This resolved the error for me – thanks to Islevegan for his post on launchpad

Find a thorough description and how to resolve on launchpad