maybe, you use different version of python.
so, python version change is needed.
In my situation(mac os leopard),
I can't do example(e.g. Tut-Asteroids.py).
because I use different version of python.
I get over this problem.
I search Tut-Asteroids.py and
right-click and
'open application by...'
'python launcher.app(2.5.4)'
and game worked.
