failure with local file upload

hsewell,

I haven't used C# or Unity, but when uploading a local file (e.g. using curl) the POST command looks something like this:

curl -F "api_key=API_KEY" -F "track=@music.ogg""http://developer.echonest.com/api/v4/track/upload?&filetype=ogg"

So try leaving off the Content-Type and URL fields.

David