Basic guide to the Box API doesn't work for me
You need to replace 'FOLDER_ID' with '0' in the URI to get the contents of your root folder i.e.
curl https://www.box.com/api/2.0/folders/0 \-H "Authorization: BoxAuth api_key=YOUR_API_KEY&auth_token=YOUR_AUTH_TOKEN"
Also, as a sidenote, it's generally never a good idea to post your auth token/api key to public forums such as this.