Hi there!
Oh boy... I had made a patch for compatibility with CGMZ_ToastManager in previous versions, but I completely forgot to double check that after 1.6.1 changes. I'll take a look after work, it's probably an easy fix.
As for the off topic question... if all you want is to have a key input to toggle the switch, it should be quite simple actually. Just create a new "plugin" with the following code (untested), changing <number> to your switch number:
Input.keyMapper[9] = 'tab';
var alias_sceneMap_updateScene = Scene_Map.prototype.updateScene;
Scene_Map.prototype.updateScene = function(){
alias_sceneMap_updateScene.call(this);
if(!SceneManager.isSceneChanging() && Input.isTriggered('tab')){
$gameSwitches.setValue(<number>, !$gameSwitches.value(<number>));
}
}
This should work for the map scene. If you need that to work on battle as well we would need to add a bit more of code.