Add a contrib line to /etc/apt/sources.list like this:
deb http://http.debian.net/debian wheezy main non-free
deb http://http.debian.net/debian wheezy contrib
Then:
sudo apt-get update
sudo apt-get install sabnzbdplus
Now we’re gonna edit the configuration:
vim /etc/default/sabnzbdplus
Now set:
USER=root
Note
USER should ideally be set to an unprivileged user, but it doesn’t seem to be working properly on Debian Wheezy, which still runs SABnzbd 0.6.15.
Now we’re enabling it on boot and starting it:
chkconfig sabnzbdplus on
service sabnzbdplus start
After this you can browse to the following address to finish configuration in your browser: http://127.0.0.1:8080/sabnzbd
(Or exchange 127.0.0.1 for the remote IP where you are installing SABnzbd)