Unable to install dependencies in node js

im learning node js and I just made a tutorial in which I tried to create a chat, everything works fine until I got stuck in one of the steps of the tutorial. I decided to download the source code of the tutorial to run the serena and see what the problem is. I have a folder named curso in this folder. I have two ona es chatnodejs folders and the other one is sourcechatjs, in chat nodejs I have packasge.json and server js, I ran npminstall and everything is fine. But, when I download the chat source, I put it in sourcechatjs, I opened temirnal and ran npm install and got this eror.

jhonnatans-MacBook-Pro:chat jhonnatan$ npm install
npm ERR! install Couldn't read dependencies
npm ERR! Failed to parse json
npm ERR! Unexpected token /
npm ERR! File: /Users/jhonnatan/Documents/Cursoseccion2/clasenodejs/chat/package.json
npm ERR! Failed to parse package.json data.
npm ERR! package.json must be actual JSON, not just JavaScript.
npm ERR! 
npm ERR! This is not a bug in npm.
npm ERR! Tell the package author to fix their package.json file. JSON.parse

npm ERR! System Darwin 12.3.0  
npm ERR! command "node" "/usr/local/bin/npm" "install"
npm ERR! cwd /Users/jhonnatan/Documents/Cursoseccion2/clasenodejs/chat
npm ERR! node -v v0.10.0
npm ERR! npm -v 1.2.14
npm ERR! file /Users/jhonnatan/Documents/Cursoseccion2/clasenodejs/chat/package.json
npm ERR! code EJSONPARSE
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /Users/jhonnatan/Documents/Cursoseccion2/clasenodejs/chat/npm-debug.log
npm ERR! not ok code 0

this is what my json looks like

{
// Aca definiremos nuestro package.json, lo primero es el nombre
"name": "curso",
// Luego la version del mismo
"version": "0.0.1",
// Ahora las dependencias, normalmente podrias hacer esto con npm pero es mucho mejor tener claro y ejecutar estricatemente las necesaria
"dependencies": {
    // Express el cual se encargara de ser nuestro framework en node
    "express": "",
    //los tipos de vista, jade parecido al que usa ruby on rails y swig parecido al que usa django
    "jade": "",
    "swig": "",
    // El que se encargara de renderizar los templates en un contexto
    "consolidate": "",
    // y por ultimo el encargado de manejar los sockets :)
    "socket.io": ""
}

}

iv tried a lot, but seriously I have no idea what could be a problem, which I would appreciate if someone could tell me about the problem!