To start the installation of softaculous you need first to enable ioncube within your whm/cpanel
1- Go to "Tweak settings" search for " Ioncube" and enable it.
2- Login to your server through SSH using "Putty"
3- type the following commands
wget -N http://files.softaculous.com/install.sh
chmod 755 install.sh
./install.sh
You can now login to your WHM/Cpanel
to see softaculous installed and working fine.