Update (11/02/2016): According to Symantec, the issue should be fixed as of their latest definitions update!
Note, however, that this may not apply to future releases (that is, it may end up getting flagged again). If you’re experiencing this problem, I would suggest delaying downloading each update until they add the next release to their whitelist (or perhaps consider switching to a better antivirus).
I’ve received messages from a few users today telling me that Norton antivirus has started picking up the latest release of HDoujin Downloader as “Heur.AdvML.B”.
For some reason, the issue seems isolated to German users. I would suggest adding the program and it’s directory/download directory to your exceptions list for now, though some users have reported that this is ignored and the program is flagged regardless.
One user has also reported that their downloaded files were also flagged and deleted by Norton, so be careful.