I wrote a Tkinter application that runs fine with Python 2.6.5 and 2.6.6 on a Windows 7 (32-bit version) machine. The same app fails with 2.7.1. Below is the debug output:

c:\ISS\ledmatrix>led-display.py
Traceback (most recent call last):
  File "ledmatrix.py", line 2263, in <module>
    LEDMatrix()
  File "ledmatrix.py", line 1427, in LEDMatrix
    root = Tk()
  File "C:\Python26\lib\lib-tk\Tkinter.py", line 1643, in __init__
    self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: Can't find a usable init.tcl in the following directories:
    {C:\Python27\tcl\tcl8.5} C:/Python26/lib/tcl8.5 C:/lib/tcl8.5 C:/lib/tcl8.5 C:/library C:/library C:/tcl8.5.8/library C:/tcl8.5.8/library

C:/Python27/tcl/tcl8.5/init.tcl: version conflict for package "Tcl": have 8.5.8, need exactly 8.5.2
version conflict for package "Tcl": have 8.5.8, need exactly 8.5.2
    while executing
"package require -exact Tcl 8.5.2"
    (file "C:/Python27/tcl/tcl8.5/init.tcl" line 20)
    invoked from within
"source C:/Python27/tcl/tcl8.5/init.tcl"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 [list source $tclfile]"


This probably means that Tcl wasn't installed properly.

Martin, any ideas?

Jack, I would wipe out the tcl directory and rerun the 2.7.1 installer, selecting just the tk/tcl/idle option. I have trouble believe that every 2.7.1 install on win7 is bad.

I'm closing this ticket because the op hasn't responded in two years and nobody has reported the issue ever since.