From the error message it looks like some files are missing. I run the same version of Ubuntu, and I have gimp installed. This file does exist for me.
I checked to see what package owns this file using the dpkg command:
Code:
dpkg -S /etc/gimp/2.0/gtkrc
This command told me that the specified file is owned by the package "gimp-data". Maybe you don't have this package installed?
If you don't have this installed, it's weird - your package manager should pull it in automatically when you install the main gimp package. How did you install gimp?
Oh, once we've got the problem sorted out, I have a short lecture for you about running as root. Remind me later.