Grunt-open: Spawn ENOENT

I keep getting "Warning: Spawn ENOENT" problem when I am running grunt-open.

My setup

I have all my project files on Google Drive. I am doing my development on the files directly on them (using Google Drive desktop).

I just want to open the index.html file when I run grunt. Just that simple.

Part of my Gruntfile.js

 open: {
  all: {
    path : 'index.html'
  }
},   

But I couldn't get it working? What am I missing?