I have installed your plugin into my wordpress. I followed all of the directions ... aws keys then amazon assoc id.... plugged them all in and then hit the save button... then test. The testing keeps failing and im not sure why. I have even created new secret keys thinking I put it in wrong but it still wont work.

What could be wrong with the setup?

May be your secret credentials are not registered for using with amazon products advertising API. This youtube video will help you how to do this. And also this amazon forum topics will let you know more. Hope this will solve your problem, if you want to know more about Getting Started with Product Advertising API then check amazon docs.

Please also keep in mind you must select the right country for which you have registered or become an associate, say if you have signed up for US country then you select the US country from the Codeshop menu Settings page country selection drop down menu. So other countries will not work with your associate tag.