A non-numeric value encountered in

Hi,
After I have restored my multisite for testing, I encounter with this error (Warning: A non-numeric value encountered in /var/www/html/websitesparaigrejas.com.br/web/wp-content/plugins/pro-sites/pro-sites-files/lib/ProSites/View/Front/Checkout.php on line 556) on the ProSite Registration page.
I tried the restoration process again e again and obtained the same error.