This means that the /etc/apt/sources.list.d/yannubuntu-boot-repair-precise.list file is incorrect. This is due to a bug of the "add-apt-repository" command.
Originally Posted by Smokin Whale
To fix this problem, please :
- if you have this problem on a live-session Ubuntu, just reboot on the live-CD, and re-install Boot-Repair.
- if you have this problem on an installed Ubuntu, open a terminal and type the following commands (replace "precise" by your Ubuntu version if necessary):
echo 'deb http://ppa.launchpad.net/yannubuntu/boot-repair/ubuntu precise main' > /etc/apt/sources.list.d/yannubuntu-boot-repair-precise.list
then install Boot-Repair if necessary:
sudo apt-get update
sudo apt-get install boot-repair
EDIT: i modified Boot-Repair so that it should not be affected by this bug any more.