FrontPage uploads a folder named _vti_cnf to all of the directories that are managed with FrontPage. When this folder is present in the admin directory and its subdirectories, the themes directory and its subdirectories, and the prodimg directory, it somehow interferes with AShop. Removing the folder usually fixes the problem. FrontPage also installs a hidden file in the ashop root directory, which can be in the way when using OrderForm, but doesn't seem to interfere with catalogue.php or the other front end scripts.