I wonder if this is network lag or poor PC performance. Is it that the game has a low FPS, or is it that you're dropping because of no response?
It shouldn't be the PC performance, as you've tried setting the settings to minimum, and this shouldn't change over time. When you say you can't bet, are you sure you're trying to bet during the first 50 frames of the fight? If not, you can't place your bet.