The system is supposed to prevent multiple votes from the same user, and shouldn't register when you vote a second time after you refresh the page. If there's a bug in it, I guess there's nothing I can do except find another rate hosting site.
As for the idea of a committee or board of judges, I wouldn't know who to ask. To be fair it would have to only be people not involved in the competition. Maybe for the next competition someone else might want to help out with organising these sorts of things, but it has been a little tough running the whole show by myself. I guess I felt it was fairer to let everyone vote for each of the games, because there are hundreds of people from around the world that can participate in the rating process then.