npm unable to install dependencies - node.js

Question

I'm trying to install some npm modules and all goes fine until I try to install the dependencies of the installed modules. npm shows this log:
$ sudo npm install -g
npm ERR! addLocal Could not install .
npm ERR! Error: ENOENT, open 'package.json'
npm ERR! If you need help, you may report this *entire* log,
npm ERR! including the npm and node versions, at:
npm ERR! <http://github.com/npm/npm/issues>
npm ERR! System Darwin 13.2.0
npm ERR! command "node" "/usr/local/bin/npm" "install" "-g"
npm ERR! cwd /Users/roemerbakker
npm ERR! node -v v0.10.26
npm ERR! npm -v 1.4.21
npm ERR! path package.json
npm ERR! code ENOENT
npm ERR! errno 34
npm ERR!
npm ERR! Additional logging details can be found in:
npm ERR! /Users/roemerbakker/npm-debug.log
npm ERR! not ok code 0
$
Also tried the command without -g but it doesn't work either.

Answer 1

There is no need for this. When you install a npm package with npm install <package name> (globally or locally), it already installs all of its dependencies on its own.
You only need the npm install command when you checked out an Application with a package.json-File to install the APPLICATIONS Dependencies.

Answer 2

If you want to upgrade ALL global packages, you should use:
npm update -g