How does one install grunt on Ubuntu 13.04?

I've attempted to install it via NPM:

sudo npm install -g grunt

Then when i run grunt:

grunt

But it doesn't seem to work it throws an error:

path.js:313

        throw new TypeError('Arguments to path.resolve must be strings');

              ^ TypeError: Arguments to path.resolve must be strings

    at Object.exports.resolve (path.js:313:15)

    at Object.<anonymous> (/usr/local/lib/node_modules/grunt/bin/grunt:13:16)

    at Module._compile (module.js:456:26)

    at Object.Module._extensions..js (module.js:474:10)

    at Module.load (module.js:356:32)

    at Function.Module._load (module.js:312:12)

    at Function.Module.runMain (module.js:497:10)

    at startup (node.js:119:16)

    at node.js:901:3

Here's some information about what version of node i have:

$ npm -v                                                                      

1.3.8