I just purchased Crysis 3 through the Origin app store on my PC running windows 8.1 with an Nvidia GTX 660 Ti video card. It's a very new system build with all the latest patches and drivers.

When installing through Origin I get an error:

DirectX Setup Error: The cabinet (.cab) file is not signed

I can't get past it. I tried to manually install DX9 but it says I'm current. DX11 is part of windows 8, and all my other apps work including Star Citizen Hangar module (built on crysis 3 engine), Battlefield 4, latest Splinter Cell, latest Assassins Creed and more. The Crysis bundle included Crysis 2 which installed and runs fine.

Any ideas how to resolve this?