On Win7, I can replicate the problem with 64-bit Python 3.2.3. However, it does not occur for 32-bit Python 3.2.2.

This problem is not due to IDLE. There is a problem with the 64-bit version of tkinter's file dialog. From a 64-bit python environment, bring up the dialog with:

    import tkinter.filedialog
    tkinter.filedialog.asksaveasfile()

and repeat the steps 3-6 from msg144106. It crashes. Repeating this with a 32-bit python environment does not have a problem.