Fantastico is not installed at the default location

When you are getting following error while trying to access fantastico.

Fantastico is not installed at the default location
/usr/local/cpanel/3rdparty/fantastico. Either move the Fantastico directory
from it's current location to /usr/local/cpanel/3rdparty/fantastico OR
enable ioncube loaders in WHM -> Tweak settings.

Try following solutions:

cp /usr/local/cpanel/3rdparty/etc/php.ini /var/cpanel/3rdparty/etc

Other Possible Fixes

You may want to first try enabling ioncube in WHM->Tweak Settings

Second you may want to try to update fantastico with  

cd /usr/local/cpanel/whostmgr/docroot/cgi/fantastico/scripts/ ; /usr/local/cpanel/3rdparty/bin/php cron.php

Third you may want to rebuild cpanel's php with /scripts/makecpphp

Fourth you may want to try a cpanel update with /scripts/upcp --force