Doesnt Work

THis is the message I get in the blog post

Warning: ksort() expects parameter 1 to be array, null given in /homepages/35/d116894064/htdocs/bulkbycho.com/wp-content/plugins/wpcalc/public/partials/public.php on line 9

Warning: Invalid argument supplied for foreach() in /homepages/35/d116894064/htdocs/bulkbycho.com/wp-content/plugins/wpcalc/public/partials/public.php on line 10

So how do you fix this where is the installation guide and set-up located for this plug in

The page I need help with: [log in to see the link]