Everything seems fine with the log. Is this your first time? First of all, for clarification, you cannot capture the game while you are alt-tabbed out of the game. It will only capture when you are actually in-game. So make sure to test with a recording or have someone verify if it's working as well.
Also, you're not using those video drivers (mentioned above) are you? They're known to cause problems I believe. Wait for official certified drivers rather than the latest.