Are you running anything else that might be stealing focus while you're playing? There's an admin at the VA forums that talks about that:
https://voiceattack.com/SMF/index.php?topic=1323.0 . Check out different settings for the "send this command..." and mess with them to see what works best, regardless of if it makes sense.
edit* here's another one that may help, although it looks like you've tried some of it...did you try turning the response 'down', i.e. <.1?
https://voiceattack.com/SMF/index.php?topic=53.0 end edit.*
For those having recognition issues, even with training, sound settings can mess up VA. I always have to make sure there aren't any added effects turned on, like 'smart volume' or 'noise reduction', etc, because when those things are enabled, VA has serious trouble recognizing anything, and when they are disabled, VA recognizes things perfectly.
Last, I use VA while the game is blaring out my 5.1 system, and don't have issues. I have all my ED commands preceded by "python" so VA won't get confused. For example, I say "python run" and it sets my pips for 4/2/0. That way, random phrases wont trigger VA.
Good luck, voice recognition can be a pita.