I have the problem described in issue6512 and here is some information 

Python version - hand compiled on Ubuntu 9.04:
Python 3.1 (r31:73572, Jul 18 2009, 11:13:40) 
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import tkinter
>>> print(tkinter.Tcl().tk.call('info', 'patchlevel'))
8.5.6

The previous Tcl/Tk version I had initially installed was a 8.4.x
version - which fails on Control-2 error described in detail in issue6512. 
- I decided to upgrade Tcl/Tk to version 8.5. 
- So I made a "make distclean" 
- copied the contents of /usr/include/tcl85 one level higher, so Python
could access the necessary tk.h and tcl.h files
- cd to my Python 3.1 source
- ./configure
- make 
- sudo make install

and tested again and my test program is now happily responding to a
Control-2 keystroke.