51 packs.The number of packs I've run with Y and Z names suggests something else may be in play. How many girl packs are you rocking?
Tested some more and I think I found something? I removed the Zoey pack, made the new last girlpack (alphabetically) a firstgirl, and tried to make a new Scramble game. It crashed again.
So I guess there's an off-by-1 error where the last girlpack in the folder isn't recruitable?