My numbpad keys do not always work or sometimes pressing the same key gives a different view. I never know what view I am going to get when I push the key that is requested in the tut.
Don
Make sure your Num Lock is on. What kind of keyboard do you use? If you have multi functional keyboard like I do, hitting a wrong key will mess you up. My keyboard has Function Key lock button. One day I accidentally hit that key and all the Function keys stopped working!
Or may be your keyboard is about to go bye bye. Try plugging in a different keyboard.