Reinstall softaculous

mkdir -p /root/softaculous_reinstall_backup
cp -pv /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/enduser/universal.php /root/softaculous_reinstall_backup/
cp -pv /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/enduser/iscripts.php /root/softaculous_reinstall_backup/
cp -pv /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/enduser/categories.ser /root/softaculous_reinstall_backup/
cp -Rpv /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/conf /root/softaculous_reinstall_backup/
rm -Rf /usr/local/cpanel/whostmgr/docroot/cgi/softaculous
wget -N http://files.softaculous.com/install.sh && chmod 755 install.sh && ./install.sh
cp -pv /root/softaculous_reinstall_backup/universal.php /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/enduser/universal.php
cp -pv /root/softaculous_reinstall_backup/iscripts.php /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/enduser/iscripts.php
cp -pv /root/softaculous_reinstall_backup/categories.ser /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/enduser/categories.ser
cp -pRv /root/softaculous_reinstall_backup/conf /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/conf

or

wget -N http://files.softaculous.com/install.sh
chmod 755 install.sh
./install.sh --reinstall

also, a way to debug

/usr/local/cpanel/whostmgr/docroot/cgi/softaculous/cli.php --repair