Jagif not working at all

Dear VillaTheme,

Thank you for your great plugins. I’m a fan. I’ve recently purchased another one, that is: Jagif plugin. However in this case I’m encountering some major problems, as nothing seems to work. Gift cannot be seen on product’s single page or shop page. When I go the shop page (or any hsop category) I see the following error -> please look at the attachment.

If you could please help me out thatw ould be great.

Kind regards.