you might be having an incompatibility
Try these steps:
Delete the device from the device manager. (If you're using a laptop be sure you are removing the usb keyboard)
Restart your computer.
Let your OS find and install it. (you may have to click "search for new devices" under Device Manager.
I'm having a keyboard problem too now. My USB keyboard is typing numbers instead of letters. If you have any idea how to fix it please check out the following link: http://ccm.net/forum/affich-970356-a4-tech-gk-300a-typing-numbers-instead-of-letters