@Nate
To me, your unfortunate case seems a clerical blunder. In CE 2012 we saw Ijaz Zardarir's DMC showing him failed in IR but he was not only called for viva but also allocated as well. Moreover, there is another similar case I personally came cross. I met xyz in foreign office (FSP allocatee) who hails from FATA. He told me once that he was failed in one of optional subject but was allocated. So brother! your case is very strong one. Looking at possitive side of your tragedy, I think you must feel yourself lucky and unique in one way or other because, FPSC will have to concede their mistake sooner or later and you will be called for viva (I am dam sure). Lucky or unique in a sense, for you will be the only person knowing his written marks before walking into interview room.
My ernest prayers with you.