ANSWER:

On Ubuntu 12.04, your rc.local should be owned by root. It’s run by root, on startup.

You can sudo -u to run things as another user in rc.local, but I admit that in nearly every single case of using rc.local I’ve come across, I’ve found it far simpler to use Startup Programs instead.

I suppose your mileage may vary. I’m afraid I don’t know why your rc.local is owned by your user.

Scaine from http://askubuntu.com/questions/298676