I can't save a book after adding image and resource for upload with Amazon Web Services

I need help with this. I am creating a demo book store with ruby and amazon web services. I have installed the gem 'aws-sdk' and everything works fine until I try to create the new book with the image and resource. I get the error listed on the link. "app/controllers/books_controller.rb:29:in `create' " (sorry I added the Full Trace as I thought that would help)If I remove the line of code that it suggests, it works, but the book doesn't show up in the dashboard.

Let me know if you need anything from me. I haven't pushed the latest commits to github because I don't want any errors, but if need be, I will. Here is the latest repo without those features.