I am currently using the Marmalade SDK on my Windows machine to build an app. I am trying to test the app on an iPhone, and downloaded the iPhone Configuration Utility in order
I had the same problem and found the answer on one of the Apple forums. It is recent problem for those running 64-bit Windows and updated iTunes to latest 12.1 version.
This iTunes version replaces 32-bit Apple Mobile Device Support with 64-bit version which iPCU doesn't support as it is 32-bit.
The way to resolve it is:
Screenshot for your convience
Note: If you still have to use iTunes, you'll have to use 12.01 version until lazy asses from apple fix that.
Edit: Apparently they are not lazy but selfish pricks. iPCU does not exist anymore. It was replaced with Apple Configurator which was not released for Windows.