Baronet on "[Plugin: WP e-Commerce] Error 404 - not found on Productspage"

Store URL: http://mandula.com/online-store/new-arrivals
WordPress version: 3.8.1
WP e-Commerce version: 3.8.13.4
Gold Cart version: 2.9.7
Theme: Blackout

I didn't create this website but was asked to fix the error. From the homepage http://mandula.com/ if you click on "Online Store" you get an "Error 404 - not found". In the backend there is only the shortcode [productspage]on that specific page, and we can see the e-commerce shopping cart logo on the visual side.

Everything else works fine.

Any ideas?

Thanks

https://wordpress.org/plugins/wp-e-commerce/