is there anyone around who this whining works with? In my house, unfortunately Daddy doesn't always mean no (grrrr) and his mind can be changed quite quickly! Mummy on the other hand is firmer and usually means what she says, that doesn't stop them trying tho!
My little girl, although younger than your two, is well and truly in the whining phase, i just ignore her if i can, but can see that's going to lead to time out soon in the future as sometimes it just doesn't work