Odd problem

I have a weird problem with dolphin build 3661. It does not allow me to configure the controller plugin or even select it. I try and run a game but it says that that there is an error reading the pad plugin and that it cannot init core. What does this mean and how do I rectify it? I have the pad plugin that came with the emu and even tried using the pad plugin from an old dolphin build but the emulator does not even pick up the pad plugin. What do I do?