tk_v_raw.py is not obviously related to this issue. First, you only use tkinter in the main thread. Second, it works on Windows 7-64, 3.4 Idle.
>>> 
Yes? > abc
Got cmd abc
Yes? > def
Got cmd def
Yes? > 
It also runs in the console on 2.7, 3.3, 3.4. The main problem is that closing the Label window does not stop while True: in the thread, making a graceful stop difficult. The loop needs
        if cmd == 'q': break

Keith, did you install the appropriate ActiveState tcl/tk, as described here: http://www.python.org/download/mac/tcltk/