Correct it isn't done downloading yet. If it is hanging while you are extracting this can happen for a couple of reasons. First you may have chosen to download the install files to your Applications folder which means they will never be done extracting because the Adobe Download Assistant can not write there. Second reason could be because you opened the DMG before the download was completed. For either reason please cancel the download and try again this time I would recommend choosing the default location of your User folder.