I’m having this problem too only it happens as I’m setting up a product for the first time. I’m trying to set up a download-only store but that checkbox keeps unchecking when I update the page. I’ve just start using version 5.02 today with WordPress 2.9.2.
To update my previous post, not only can I not see images in my teaser but the everything is completed unformatted. I’ve found the bit in index.php which prints the_content and compared it to other theme files (the WordPress Default theme for instance), but can’t work it out.