Stack inspection fails in interpreter

[Helge Stenström]

A little program used to demonstrate introspection fails when run inside Emacs, using c-c c-c in python-mode.el. The same program works when run from the command line or from within python.el. It fails the same way with Python 2.3.4 on Linux and Python 2.5 on Cygwin on Windows.

The essence of what fails is probably:
   import inspect
   stack = inspect.stack()
   s = stack[1][4][0].strip()
where the last statement fails because the structure of stack is not what's expected.
(TypeError: 'NoneType' object is unsubscriptable)