Yes, I am formatting them with the SD formatter from the SD association. We're not talking about a half-dozen cards, I have successfully used hundreds of low-capacity cards, but have problems with about 150 cards, all Nokia 128mb or 256mb. All of the cards that cause problems have similar markings (the text on the card is vertical, not horizontal.) I don't believe the cards are "duds", but perhaps a different type of card?
My module is powered from the Due 3.3v output.