Hi onetwothree,

I wouldn't recommend using GrubEd these days - there are much more advanced grub boot editors available now. That said - if you still want to run GrubEd (there's no real reason why you shouldn't - just that it's not all that great compared to others available) - then Kubuntu might be causing you problems. Can you provide the actual error message you get, copied from the terminal?

Make sure the script is marked as executable before trying to run it:
chmod +x ./install