I've managed to reproduce the issue on Win2k8R2. It's coming from ImageMagick not being installed/configured correctly.
These are the steps I took to fix the issue:
Go out and install the latest version of ImageMagick
After running the installer make sure that you close the command prompt from which you are running NodeBB.
Open a new command prompt and rerun node app.js
The problem should be fixed! 
It's merged with the docs branch, which isn't being used though. :<
Cool, would it be possible to merge my most recent change into master?
Hey all, I noticed that there's a docs branch that hasn't been touched since the end of April (less a pull request I put in today). Is this branch still active? I have another pull request waiting to bring it up to date with master if it is.
You can check to see if nodebb is running with ps -ewwo pid,args | grep nodebb.
I've managed to reproduce the issue on Win2k8R2. It's coming from ImageMagick not being installed/configured correctly.
These are the steps I took to fix the issue:
Go out and install the latest version of ImageMagick
After running the installer make sure that you close the command prompt from which you are running NodeBB.
Open a new command prompt and rerun node app.js
The problem should be fixed!
I'll try to reproduce the error and see if I can't fix it.
Looks like a permissions error, but their solution is to use require('gm').subClass({ imageMagick : true}).
Maybe Linux is the answer for you after all! 
I can't blame you; Windows can be pretty finicky sometimes. If you have UAC enabled, I think you might still have to specify that you want to run your command prompt in Administrator mode. I'd double check that just to make sure.
I found someone who was having somewhat similar problems with node's GraphicsMagick (gm) plugin on StackOverflow and it looks like their solution involved changing require('gm').subClass({imageMagick:true}) to require('gm'), as well as running node from Administrator mode.
Have you tried running node from a command prompt in Administrator mode ('Run as Administrator')?
