Amazon product import type

All products imported using the Amazon Import Tool are done so with the product type being set to “Downloadable Product” rather than “Affiliate Product”. With it like this the “Add to Cart” button does not redirect to Amazon it adds it to my site basket. If I do then click checkout now, I am directed to my sites checkout but the continue button never redirects (looks like it is trying to send me to https:\\www.amazon.com\gp\aws-merge.html?cart…. but never does) me to Amazon.