I just upgraded to wp ecommerce version 3.8.1 and upgraded WP at the same time to 3.1.1 for a site that's still in the build stage but about to go live. Every thing seems to be fine, but... There's always that "but..." If you click on a product category, you get a page that's pretty much broken. No links. Text that should be part of a script displays, all fonts default size... If you click the "all products" page, everything works perfectly.
View a broken category page here: http://tea-sanctuary.com/products-page/bulk-herbs/
View a properly displaying page here: http://tea-sanctuary.com/products-page/
I've pretty well narrowed this down to a theme problem. Everything works fine using the Twenty Ten theme. This site is currently running Atahualpa 3.6.4 - but I had a similar problem running version 3.5.1.
Any help would be greatly appreciated!