Running 10.9.3 on a mac mini (i7). I was having problems with a specific host (can't recall which one) never connecting and decided to try to downgrade from jdownloader 2 to jdownloader. Found that my download list was not maintained and while I was expecting to have both jd2 and jd installed and running at the same time, installing jdownloader appears to have removed jd2 from my system entirely.
Decide to reinstall jdownloader 2. I download the jd2setup.dmg file. (edit: from
http://board.jdownloader.org/showthread.php?t=54725 the 10.7 or higher link) Click on it, click on the jd2 file in the disk image and get an error. "JDownloader installer- error downloading the Java (TM) runtime environment. please check your internet connection and start set up again"
Rebooted macos and still having the problem. Internet connection is fine.