http://en.wikipedia.org/wiki/Ludo_%28board_game%29

Well looking at the rules of Ludo on wikipedia, it says that a roll of a six earns a bonus roll. I did not see where it says in there that the bonus roll MUST be used with the same pieces that the original 6 was moved with, and in addition to that if the bonus roll can not be used, the original 6 is now void.