1. Login to the server WHM as root user.
2. First check if ioncube loader is installed, if not, install it.
Sometime it is not enabled, so enable the ioncube loader from WHM.
Main >> Server Configuration >> Tweak setting >> php --> mark the ioncube.
3. Login to server via SSH.
cd /usr/local/src
wget -N http://files.softaculous.com/install.sh
chmod 755 install.sh
./install.sh
4. Restart cpanel (/etc/init.d/cpanel restart).
5. Now go to : WHM >> Plugins >> Softaculous - Instant Installs
Reference:-
http://www.softaculous.com/docs/Installing_Softaculous_in_cPanel
