I was using Amazon Machine Tags version 1.04 which was working well on WordPress version 2.32.
When I saw the notice on my ACP plug-ins page, I upgraded to 1.06. The plug-in no longer worked - no jacket image, no link, nothing - everything just vanished.
I re-uploaded Amazon Machine Tags version 1.04 (I've gotten into the habit of saving previous working versions for WordPress and vBulletin plug-ins) to my server and everything works again.
Nothing else has changed on my blog.
I conclude that there's an error in your upgrade.