It does sound as though there may be some learning difficulty there, especially if you have tried one hand (single stave presumably) and she still can't manage it. There are some books with different coloured notes in (sorry can't remember what they are called - someone will no doubt remind me).
Perhaps try getting her to move some notes around on a big stave (You could use buttons or cut out cardboard notes) - some kids learn better by doing rather than looking - counting notes up from the bottom line.
I hate to say it, but it sounds as though you've tried pretty hard - you can't win every time. How badly does she really want to carry on? It sounds as though her aural skills are pretty weak if she doesn't even recognise when she is going wrong - perhaps some work on that might help.
Good luck!