I don't see how win->win could be uninitialized.  curses.newwin() creates 
a PyCursesWindowObject using PyCursesWindow_New(), which always fills in
the ->win field.

I'm puzzled by the 2007-06-28 traceback.  Pycurses_new_panel has args =
0x0000000110246dc0; args should be a Python tuple containing the
function's arguments.  But the new_panel call has
win=0x0000000110246dc0, the exact same pointer, which is obviously
wrong.  The code in PyCurses_new_panel does win->win, though, so the
pointer should be different.  Perhaps the traceback is wrong?  Or
perhaps this is a code-generation bug affecting PyCurses_new_panel? 
(But that function is small and straightforward -- I find it hard to
imagine a compiler getting it wrong.)