I have had a Zen Cart store for several years with everything working fine. I have neglected it for several months and just recently tried to add new products (downloadable). A test purchased revealed no download button on newly added products. In checking I discovered the "green radio button Filename: ProductName.zip" is not appearing on the "Adding New Attributes" section. The old products appear to be operational. This is just occurring with new products added. I assume I have forgotten a crucial step but can't seem to find it.

Any help would be greatly appreciated.