Hello, I have the same problem, my controls work fine (axis tune, buttons, etc) while in the options, but when I start the sim everything stops working, no keyboard or joystick input at all, except ESC. I can only use the mouse.
If I click Adjust Controls in game, nothing happens and I'm forced to close the game.
Trying to download and re-install the whole DCS World ATM, hopefully that fixes it.
I'm using a Thrustmaster Warthog and ver. 1.2.7.23097
It's really game breaking for me, and I was just about to buy FC3 too..
edit: fixed after re-installing