I can confirm that the workaround from "Toby (to-mueller87) wrote on 2012-08-09" worked for me as well (Bug #1041915 that I filed is a duplicate of this one) .
I did this:
cp 40-libsane.rules 40-libsane.rules-2012-08-26-for-scanner-breaks-apt
sudo rm 40-libsane.rules
Then the repair using the "Ubuntu Software Center" worked.
I can confirm that the workaround from "Toby (to-mueller87) wrote on 2012-08-09" worked for me as well (Bug #1041915 that I filed is a duplicate of this one) . rules-2012- 08-26-for- scanner- breaks- apt
I did this:
cp 40-libsane.rules 40-libsane.
sudo rm 40-libsane.rules
Then the repair using the "Ubuntu Software Center" worked.