I just want to do a quick check if the latest version of WordPress 3.3 has changed the get_the_post_thumbnail function at all.
I put togeher a quick mod for th last viewed post to work with wp ecommerce 3.8.7 and everything was working great on the least version of wordpress.
Once updated to wp 3.3 the call for post thumbnail stopped working. Also what I noticed was that uploading product images on wp ecommerce 3.8 also stopped you from setting an image as the featured thumbnail.
I just want to check that no changes were made to the get_the_post_thumbnail before starting to mess with wp ecommerce core code to see if the issue is there (personally I think it's all part of the wp3.3 and tinymce situation)