ReferenceError: window is not defined

I'm trying to run the Pocket-Island game by Wooga and have installed all prerequisites listed at that page:

gem install rake
npm install -g less
npm install -g jslint
...

And then build the program successfully by running

rake all

And have now a new build directory:

app.js  css  images  index.html  ipad.html  templates  version

The app.js is 400k and looks like a minimized JavaScript file.

Then I try to run it with node:

#node ./app.js

/home/afarber/src/Pocket-Island/build/app.js:1
window.wooga.cas
^
ReferenceError: window is not defined
    at Object.<anonymous> (/home/afarber/src/Pocket-Island/build/app.js:1:63)
    at Module._compile (module.js:446:26)
    at Object..js (module.js:464:10)
    at Module.load (module.js:353:31)
    at Function._load (module.js:311:12)
    at Array.0 (module.js:484:10)
    at EventEmitter._tickCallback (node.js:190:38)

Being a complete node.js newbie, I suspect I'm missing something very obvious. Does anybody have an advice for me please?

I've looked into app.js and there is no window.wooga.cas, but there are several following variables:

window.wooga.castle.levels = .....
window.wooga.castle.entityDefinitions = .....
window.wooga.castle.version = "38da43a566503f3043576dafaf77f89363017397" ;
window.wooga.castle.tutorial = ....

So I think app.js is ok, but I must install it somewhere or maybe tell it where to find standard libraries? (I've installed node.js under /usr/local/ )

I'm using a CentOS 6.2 and I'm actually an experienced Linux user.

UPDATE: More info (not sure if helpful):

# npm root
/home/afarber/src/Pocket-Island/build/node_modules
# npm --version
1.1.24
# node --version
v0.6.19