Hmm...I have a mac and it works fine. It is the same specs as yours. It is probably the computer, though since macs are so reliable I don't know what to say. Just call customer service, and if they even answer, tell them your problem and see if they can help. The number is in the FAQ. Just trying to find this out for you!
-Bebop McBrains
P.S. Sorry if I sound like one of the automated Bug Reports!
P.P.S. EDIT: if you hold down fn and press and hold left, you see gags, right, you see TTasks, and up and down are like Page Up and Page Down. Ctrl, if you hold it down, keeps you jumping.