because it was their software, It shouldn't be for use if not work...
This wallet is a scam! this is my opinion!
At the top of the Dark Wallet page with parts in bold:
"IMPORTANT The wallet is Not Stable, and at this point you should use it with real money only at Your Own Risk."
(see
https://wiki.unsystem.net/en/index.php/DarkWallet/Alpha5 )
This is still alpha software, not even beta. They are working out the bugs, and it should only be used on test net.