Java compilation error (Minicraft by Notch)

I'm having trouble running the game that Markus Person Notch created in 48 hours known with Minicraft (do not confuse it with Minecraft), I downloaded the source code but it gives the following compilation error:

Exception in thread "Thread-0" java.lang.IllegalArgumentException: input == null!
    at javax.imageio.ImageIO.read(ImageIO.java:1348)
    at com.mojang.ld22.Game.init(Game.java:118)
    at com.mojang.ld22.Game.run(Game.java:136)
    at java.lang.Thread.run(Thread.java:745)

And the game window stays white, nothing happens.