Apple Aluminum keyboard(wired) doesn't work

Hi,

I recently bought an Apple Aluminum full size keyboard(wired) for my 2008 Mac Pro tower. After I connect it to my tower, it doesn't work. I tried to use the keyboard setup from control panel to recognize the keyboard by pressing the key right to the shift key(Z key). It just hangs on the "identifying your keyboard" screen.

Can someone help?

Thanks.

Shaun