Help says: "You can vote 30 times per UTC day, plus 10 more times on questions only." http://electronics.stackexchange.com/help/privileges/vote-up

What exactly does it mean? Today I have up-voted 37 times. So, I would expect to be able to up-vote questions at least.

And now I am not allowed to vote for answers nor questions. Message is: "Daily vote limit reached; vote again in 16 hours"

Am I missing something? Or is there some bug?