I have a black Macbook and a Midiman 49 USB MIDI keyboard. I have added a MIDI device, etc. through the proper control panel, but when I go to record in GarageBand, the computer will not recognize the keyboard, i.e. there is no sound--even though it says "now there is one MIDI device." The same setup works on my G4 iMac. Any ideas? Both machines run Leopard.