Same here... at first it looks like it's working fine, it appears I can sample data to the card and read it back. But once I've reset the board and try and read the data back I am presented with all zero's. 
I too can confirm that reading and writing appears to work even without a card in the slot, despite the fact that it says initialisation failed and doesn't show any card statistics. :-/
With a card in the slot I get reasonable looking card statistics (size: 125698048 for a 128MB card) which suggests it can see the card.
Which again raises the question, what are we missing here? Any ideas?
I will be sure to post if I make any further discoveries.
Thanks all! 