I've been looking into this problem for myself for almost a day and finally had a breakthrough. Try this:
- Setting the PYTHONPATH / PYTHONHOME variables
Right click the Computer icon in the start menu , go to properties. On the left tab, go to Advanced system settings. In the window that comes up, go to the Advanced tab , then at the bottom click Environment Variables. Click in the list of user variables and start typing Python, and repeat for System variables , just to make certain that you don't have mis-set variables for PYTHONPATH or PYTHONHOME. Next, add new variables (I did in System rather than User, although it may work for User too): PYTHONPATH, set to C:\Python27\Lib.
PYTHONHOME, set to C:\Python27.
Hope this helps!