Marketpress--can't insert media to product

I've installed Marketpress and activated it, and imported products from a .csv file. Unfortunately, I can't insert an image using Add Media. I upload the image, click Insert into post, and the overlay window disappears but no image is inserted. I can insert images in this manner for regular posts.

I've deactivated all plugins except for Marketpress (obviously) and even with only that plugin activated, I still can't insert media to products, only to regular posts. Is there a setting somewhere that I've missed?