I don't really know the cause of your problem.

You may need to replace Tab spaces to Spaces in the pyw files.

Do you have the Adobe Digital Editions installed and registered to you?

Have you really installed PyCrypto? Try to re-install it. And make sure your Python and Pycrypto are compatible.

What OS do you use? If you use Windows Vista or Windows 7, you may need to add python.exe and pythonw.exe to the DEP exceptions.

Did you try to remove DRM from epub files? Where did you buy the epub files you have problem with?