Can you try to create screenshots for 1 and 3 ? Sounds like JDownloader is unable to move away the dlc files from your shared folder and imports it again and again. That would also explain your 2.)
After parsing the folderwatch job or container file , JDownloader moves the parsed file to a subfolder 'added'. Does this subfolder exist for you? If not, then this might be the cause for all the issues you encounter
Because JDownloader parses again and again and again....
If that folder doesn't exists, this is a sign for wrong ownership/permissions and JDownloader is unable to create/move files in that folder