... Auto Mute is a feature designed to stop you blowing up your speakers, eardrums, or just doing silly stuff with your mixes. I would leave it set to on and its default settings, to be honest -- you won't be creating anything meaningfully useful if stuff is so loud you're causing auto-mutes. It should be seen as a positive feature, even though it can be annoying when you first encounter it.
Obviously the way to react to an auto-mute event is to investigate what's happening on the offending track and make changes there. Then you're good to go. Turning the fader down is a good place to start! You could try reducing the input gain, too, if such a control exists. There are a variety of options depending on what's causing the over-loud output.
This is a good question, anyway. If you want to muck about with the automute settings they're in Options -> Preferences -> Audio -> Mute/Solo. There's a bunch of choices you can make that affect the behaviour there, inclulding the option to switch it off. But (and this is a personal opinion, of course) the defaults seem fine to me.