Marketpress main shop page next button pulling up same items

Hi there!

Just noticed a weird bug on this site I'm working on, where the "next page" button at the bottom of the main page of the shop is bringing up the same items over and over.

http://69.89.30.241/dev/frenchietest/pet-supplies-shop/

When I go to the blog page, that "next page" button is working fine. Any ideas as to what's causing that?

Thanks in advance!