There's no reason the controllers cannot work at the same time. Check your Windows Control Panel to verify that both controllers are recognized & working simultaneously. If both controllers are recognized by Windows, then you have to check the game's help pages/forum to see what the problem is. For the games I play, the game's web forum always has the best answers.
Is the wireless one specifically for windows, or normal xbox? Also it depends on whether you have the drivers properly installed and/or the game being able to recognize a local second player. I would look into all of these first.