I had problems with downloading big files, found here the same problem.
Reuploaded the DownloadModule, that solved downloading problem, but I noticed another one...
Now all my download counters are frozen, after file downloading they don't change.
Since v1.4.0 Beta 1 is due to be released for Pro customers soon, putting the time into attempting to fix this would only result in v1.4 being delayed.
I've already tested it in v1.4 and it's working fine there