I got this message when I was using Update Manager:
E:Type 'ppa.launchpad.net/otto-kesselgulasch/gimp/ubuntu' is not known on line 2 in source list /etc/apt/sources.list.d /otto-kesselgulasch-gimp-precise.list
How do I solve it?
An error has somehow crept into the PPA's sources list file. Let's just delete and re-add the PPA to fix it.
Update Manager should now work without any errors.