When i flow u your E-Commerce Guide for customizing product category i faced with this error:
{"[QueryProvider.GetQuery]: Query CMS.Product.selectversions not found!"}
I folow up these steps acording to ur ecommerce guide:
1. Go to CMS Desk -> Content and choose Products in the content tree.
2. Click New at the document action toolbar.
3. Choose the Page(menu item) document type.
4. Enter Plasma TVs as the Page name, make sure the Use page template radio button is selected and choose Products -> Product grid view template. Click Save.
Here when i click on save this error occurs.
I have your free version of Kentico cms.