This is the most common problem and it has nothing to do with Xpadder

When you connect an Xbox 360 wireless controller to your PC using the Play & Charge cable then Xpadder cannot see it. Why? Because neither can Windows!
The Play & Charge cable only supplies the controller with power. It does not send any data from the controller to the PC nor does it turn your wireless controller into a wired controller.
Even when you use the Play & Charge cable with your Xbox 360 console, the controller is still communicating with your console wirelessly. The Play & Charge cable is for power only.
To use an Xbox 360 wireless controller with Windows you need to use a Wireless Gaming Receiver. This allows Windows to see and communicate with your wireless controller wirelessly and Xpadder will then be able to see it too.