Flash player unable to proceed with the installation
I've have this problem come and go, and come back again. 

FIX: The best fix so far for me is to go back to Flash Version 13. The say Flash Player Version 13 is in "extended release". I am on Mac osx 10.7.5 the last version of mac operating system for my machine.

Find it here: for browsers, it may have the strange name "plug in content debugger", I think the word "plug in" matters for browsers. The other "projector" versions I don't know about. The "plug in debugger version 13" fixed my safari problems. 

https://www.adobe.com/support/flashplayer/downloads.html

Fix 2: You must disregard the constant signaling to update to version 15 if you are getting it. The update to version 15 may load a broken version in the browser, then you have to uninstall it with their special utility and reinstall version 13. Get the uninstall download here (or search for adobe flash uninstall on the web):  

http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html#main_uninstall

More Possible Explanation:
Apparently the weird name "debugger" means they have debugged common problems with it. Essentially you are going back to the previous version since the new one has problems loading/working (keeps getting identified as out-of-date so it won't work) but they don't want to pull the new version off the market, can you imagine that mess. Thanks Adobe for the extended release we depend on it! 

Here is adobe's comment on it: 

EXTENDED SUPPORT RELEASE - FLASH PLAYER

What is the extended support release?

Adobe makes available a version of Flash Player called the "Extended Support Release" (ESR) to organizations that prefer Flash Player stability over new functionality. We have created a branch of the Flash Player code that we keep up to date with all of the latest security updates, but none of the new features or bug fixes available in our current release branch. This allows organizations to certify and stay secure on Flash Player with minimal effort.

10/14/2014 - Updated debugger and standalone versions of Flash Player. These players contain fixes for critical vulnerabilities identified in Security Bulletin APSB14-22. The latest version is 13.0.0.250 (Win and Mac). All users are encouraged to update to these latest versions.