MarketPress category pages don't show all products and link to attachment page

#1) I have the category pages set to show 20 products per page, but only 5 appear -- leaving 4 blank spaces in the second row.

#2) When we click the link to page 2 (in the pagination at the bottom) it pulls up the attachment page for a video that's embedded with one of the products. Clicking the link to page 3 seems to work properly.

As always, your help is greatly appreciated.