I'm having the same problem, it stopped my batch of downloads atleast 90% through...I'm finding it hard to believe that there's no current fix for the resume? Here's a screenshot to explain my headache:

(I have a 250GB monthly limit, there's absolutely no way I'm going to reset the download---already tried tweaking the max conn.)

I had 2 other jD packages (megaupload) after that and they went 100% without a problem.