Can you please provide Flash player online installer (ADM) logs . This will help us to debug further.
Please follow instructions from the section (File #3 and 4: Adobe_ADM.log and Adobe_GDE.log) in the below link to get ADM logs.
For Quick help please find offline Flashplayer installer.
Click on the following Adobe link. Go down to the bottom where it says, "Still having problems?". Click on the link for your browser.
1)The install log shows nothing new. Thus the other items cannot be located either.
Since we are not able to get the exact issue, we will try to replicate the same environment and see if we can reproduce the issue.
Meanwhile are you willing to do a screen share session with Adobe engineers so that we can debug the issue on your machine and resolve it for you? You can select the time based on your convenience.
Please provide the other two log files, install.log and FlashPlayerInstallManger.log file mentioned in the Where do I find the Flash Player installation log on the Macintosh? FAQ.