Unless you know exactly what you are doing, it is a very bad idea to be using paper backups with Bitcoin-Qt.
Bitcoin-Qt creates new addresses every time you send a transaction and moves some of your bitcoins away from the addresses that you created paper backups from to these new addresses. It hides these new addresses from you, so that you don't know what they are or that they even exist. This means that the bitcoins are held at addresses that are not backed up with your paper backups.
Really?