I don't know if this will help, but here are two things I just came across when I had the same problem:
1. The ASIN on Amazon Associates Page isn't the ASIN you need. Maybe this was just a fluke, but grabbing the ASIN from the Associates Page didn't work, only after I went out to the regular product page and cut & pasted that ASIN did everything show up.
2. I also noticed that I used the wrong Access Key at first. When you go out to the IAM Management Console, you see your Access Key already there. I made the mistake of C&Ping that Key, then requesting a new Key and putting in the Secret Key from that rootkey.csv file without updating the Access Key. Does that make sense? Just make sure both Keys you used are the ones that were sent in the rootkey.csv file.
Hope these help.