On OS X the 'initialization error' usually occurs when the APP installer file is extracted/moved from the mounted DMG to some other location. If you did this, it's the cause for the error. If you did not do this, please upload the Adobe_ADM.log file, saved at ~/Library/Logs/Adobe_ADMLogs to cloud.acrobat.com using the The specified item was not found. instructions or some other file sharing service of your choice that does not require log-in to access the file.
You can also try the offline installer posted at the bottom of the Installation problems | Flash Player | Mac page in the 'Still having problems' section.