Uploaded also supports 20 for premium but it makes no sense to do this because 3-4 are already enough to get good speeds.
Too many connections can lead to a slower system and overloaded file hosters.
Please create and post a new log using the "brdebug" parameter.
How to do it under Windows:
1.Close your JD.
2.Rightclick on your jdownloader.exe
shortcut->Add " brdebug" (without "") to the end of the "Target" line, see here:
3.Start JD, provocate the bug/error and post your new log.
GreeZ pspzockerscene