I have exactly the same issue.
Managed to register the game (with the old activator, from (http://sd.stardock.com/sdactivate_legacy.zip)). The regular one just kept showing the hourglass and stayed there.
Got the sig.bin created... Got in the game.
There, when entering login/password (and I tried a lot), it IMMEDIATELY fails. Like it doesn't even check it online. VERY frustrating. Just gifted a copy to a friend. He went online... And is waiting for me. I simply can't login!!!
Can't be that difficult to get it working on Win8CP....
Battlefield 3, Mass Effect 3, Guild Wars (the first one), Skyrim, SWTOR... They all work just fine. No issues whatsoever.