Re downvoting on Meta: See the FAQ.
Voting here works a bit differently from other Stack Exchange sites. On Meta Stack Overflow, voting is used to express agreement or disagreement, not to point out a lack of quality or helpfulness. Please don't be concerned if you receive downvotes – members of the community may simply disagree with your bug, feature request, support issue, or the nature of the discussion.
Re downvoting on SO proper:
You have received one downvote to date, which cost you 2 reputation points.
The one question that you got the downvote for is
Ruby on Rails script console I can't judge on the quality of the question, but it looks fine. Maybe it was because of your (back then) low accept rate, I don't know.
I wouldn't worry about it. Everyone gets a downvote once in a while, and as far as I can judge, your contributions are of fine quality.