I'd definately try re-seating the apx card, it seems like it's not connected. Pop-up the keyboard, un-clip the small wire clip, pull out the apx card using the small plastic tab, and plug it back in again, make sure the antenna is in properly too, oh and make sure you undo the small plastic screw (which also serves as the numlock light). if you can't see whether it's un-done or not, switch the numlock light on, then when it's undone turn off the ibook and re-seat.
Sean