Ah, sorry, I forgot about that.
Nevermind, I found that I entered the command wrong. Just got it to work again by adding a /.
Oh, and if anyone else has problems with this, the commands I used were:
sudo echo "deb
http://www.geekconnection.org/remastersys/repository karmic/" | sudo tee -a /etc/apt/sources.list.d /remastersys.list
sudo apt-get update
sudo apt-get install remastersys