I have no time to figure out what the attached script is supposed to do.
 Please provide a standalone test-script and describe exactly how it
should be used to reproduce the bug.

However, I guess the problem is that the signature of
PyThreadState_SetAsyncEx is this:
  int PyThreadState_SetAsyncExc( long id, PyObject *exc)

To call this function correctly on a 64-bit system you have to set
argtypes because 'long' isn't the same as 'int' any longer.  Without
argtypes, ctypes passes a Python integer as 'int' argument.