I know this thread is old, but I've run into the same thing with two cards and wasn't sure if it was a backend problem that just needed a bit of jogging:
Hymn to Tourach is listed at $0.00 on the listing page, but has a value when you look at the specific page (http://deckbox.org/mtg/Hymn%20to%20Tourach). I also noticed for this card that the "Editions" has fallen empires 4 times (maybe corrupt data?).
The other card that's being listed at $0.00 on the listing page is Llawan, Cephalid Empress (http://deckbox.org/mtg/Llawan,%20Cephalid%20Empress). This one also has price info on the specific page, and in this case there isn't anything funky in the editions.