When you place a book or print order from Aperture, it must upload data to Apple's servers. This happens in the background after you place the order. The length of time required will vary, depending on the size of the order and the speed of your Internet connection. To be sure your order uploads completely, keep Aperture open and your computer awake until you receive an email from Apple confirming that the order has been received.
Aperture 3: Book or print order does not finish uploading if Aperture quits
A book or print order will not fully upload if Aperture quits or the computer goes to sleep before it finishes.