Trouble Creating a Package

I'm using Firefox Poster to try to create my http call to create a package in eSignLive with the API and am struggling a bit. From Poster I send a POST request to https://sandbox.esignlive.com/api/packages/ withthe content as:

{
   "name": "My Document",
   "type":"PACKAGE",
   "language":"en",application/json
   "emailMessage":"",
   "description":"New Package",
   "autoComplete":true
}

Any idea where I'm going wrong?