Ember server showing error - The Broccoli Plugin: [object Object] failed with

I'm new to Ember js and created a sandbox app. Every time I run ember s in my terminal (I'm on Ubuntu 16.04) I get these errors and warnings:

WARNING: Node v7.0.0 has currently not been tested against Ember CLI and may result in unexpected behaviour.
Could not start watchman; falling back to NodeWatcher for file system events.
Visit http://ift.tt/22TlJJ7 for more info.

Just getting started with Ember? Please visit http://localhost:4200/ember-getting-started to get going

File: /home/lykos/code/sandbox/app
The Broccoli Plugin: [object Object] failed with:
Error: watch /home/lykos/code/sandbox/app ENOSPC
    at exports._errnoException (util.js:1026:11)
    at FSWatcher.start (fs.js:1297:19)
    at Object.fs.watch (fs.js:1322:11)
    at FSMonitor._measure (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/heimdalljs-fs-monitor/index.js:66:21)
    at Object.watch (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/heimdalljs-fs-monitor/index.js:82:30)
    at NodeWatcher.watchdir (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/sane/src/node_watcher.js:144:20)
    at new NodeWatcher (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/sane/src/node_watcher.js:45:8)
    at new sane (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/sane/index.js:17:12)
    at Watcher_addWatchDir [as addWatchDir] (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/ember-cli-broccoli-sane-watcher/index.js:131:17)
    at /home/lykos/code/sandbox/node_modules/ember-cli/node_modules/broccoli-builder/lib/builder.js:93:35

The broccoli plugin was instantiated at:
    at WatchedDir.Directory (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/broccoli-source/index.js:14:31)
    at new WatchedDir (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/broccoli-source/index.js:58:13)
    at EmberApp._initOptions (/home/lykos/code/sandbox/node_modules/ember-cli/lib/broccoli/ember-app.js:200:17)
    at new EmberApp (/home/lykos/code/sandbox/node_modules/ember-cli/lib/broccoli/ember-app.js:121:8)
    at module.exports (/home/lykos/code/sandbox/ember-cli-build.js:6:13)
    at Class.setupBroccoliBuilder (/home/lykos/code/sandbox/node_modules/ember-cli/lib/models/builder.js:70:19)
    at Class.init (/home/lykos/code/sandbox/node_modules/ember-cli/lib/models/builder.js:50:10)
    at Class.superWrapper [as init] (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/core-object/lib/assign-properties.js:32:18)
    at Class (/home/lykos/code/sandbox/node_modules/ember-cli/node_modules/core-object/core-object.js:32:33)
    at Class.run (/home/lykos/code/sandbox/node_modules/ember-cli/lib/tasks/serve.js:15:19)

Livereload server on http://localhost:49152
Serving on http://localhost:4200/

And this is my package.json file

{
  "name": "sandbox",
  "version": "0.0.0",
  "description": "Small description for sandbox goes here",
  "private": true,
  "directories": {
    "doc": "doc",
    "test": "tests"
  },
  "scripts": {
    "build": "ember build",
    "start": "ember server",
    "test": "ember test"
  },
  "repository": "",
  "engines": {
    "node": ">= 0.12.0"
  },
  "author": "",
  "license": "MIT",
  "devDependencies": {
    "broccoli-asset-rev": "^2.4.5",
    "ember-ajax": "^2.4.1",
    "ember-cli": "2.9.1",
    "ember-cli-app-version": "^2.0.0",
    "ember-cli-babel": "^5.1.7",
    "ember-cli-dependency-checker": "^1.3.0",
    "ember-cli-htmlbars": "^1.0.10",
    "ember-cli-htmlbars-inline-precompile": "^0.3.3",
    "ember-cli-inject-live-reload": "^1.4.1",
    "ember-cli-jshint": "^1.0.4",
    "ember-cli-qunit": "^3.0.1",
    "ember-cli-release": "^0.2.9",
    "ember-cli-sri": "^2.1.0",
    "ember-cli-test-loader": "^1.1.0",
    "ember-cli-uglify": "^1.2.0",
    "ember-data": "^2.9.0",
    "ember-export-application-global": "^1.0.5",
    "ember-load-initializers": "^0.5.1",
    "ember-resolver": "^2.0.3",
    "ember-welcome-page": "^1.0.3",
    "loader.js": "^4.0.10"
  }
}

I did a search and found this ember cli application build fails: The Broccoli Plugin: [object Object] failed with: but didn't work, I'm not sure if its related to some previous version - I've installed ember 2.9.0.

How can I fix this?