RedOctane Metal Pad Control Box PC help

[Shrooom]

I recently went out and bought a RedOctane Metal Pad, and just today finally received the control box for the pc. I plug it into my computer through the USB slot after hooking it up to the pad, and then I started up Stepmania. However, I can't press up+down or right+left at the same time (plus all the lights go on at the same time, not that I care too much) because it doesn't register. Can anyone help me out here? I have XP btw.

*EDIT* I apologise for posting this in the wrong place (I meant for it to be in DDR Simulators). I had two different topics open and got them mixed up. As I don't see a way to delete it in editing this post, it would be appreciated if someone moved/locked this.