WP Storefront

Hello. I am using the Storefront theme (original) with the latest WordPress, to sell books and DVDs (WP-E-Commerce plugin)

In one product category I have approximately 20 books to list. However, only 10 items are displayed per page. When a user clicks on the “next” button, rather than leading them to the next 10 items it says “there are no products listen in the category”.

Any advice with this greatly appreciated.

Thanks.