The problem is, that the plugin wants you to use their function to get the posts, but what if you want to have the post inside the main query - this enables you to use the have_posts().
And when you try to set your orderby for that query - it doesn't change.
So, here is the best solution you will find all over the net -
You should update the main class function in lib/tribe-event-query.class.php:
somewhere in line 619, there is a switch for the orderby arg, add your custom case to that switch for example:
$order_sql = "EventRating ASC, " . $order_sql;
query_posts(array('post_type'=> 'tribe_events','orderby' => 'EventRating', .....
WILL FINALLY WORK