Amazon Product In a Post Plugin not working, help please

I installed a few plugins to attach amazon products on my blog but it seems that something is wrong with my settings. All plugins didn't work. There are no product appear on my post. I already insert my Amazon Affiliate ID, Amazon Access Key ID and Amazon Secret Access Key but nothing happened.

Now, I am using Amazon Product In a Post Plugin which I think is better. Can anyone figure what is wrong?

Have you tried either of these? They are free and I've had good results with them..

AmazonJS
EasyAzon

Both are free from the Wordpress Repository.