
You are going to have to make sure she can't get anywhere near your wardrobe - it seems very much as though that is her 'ideal' spot! And you might not win - if she has firmly decided on that site she might start moving pups there at any opportunity after they're born and can work herself up into a state of hysteria when her plans are thwarted! :(
Is her whelping box covered and nice and dark? I always have ours under a table with curtains all around to make a nice dark, cosy den, and the bitches always feel secure in there. So I should get that done if you haven't already.
Is the whelping box downstairs and your wardrobe upstairs? If so, fit a stairgate and don't let her upstairs at all - the stairs may become too much of an effort for her soon, anyway.
Good luck.
:)