I had the same error/issue and this how I quickly fixed it:
Step 1: Visit this site to download a previous version Archived Flash Player versions
Step 2: Download version -> (Released 9/9/2014) Flash Player 15.0.0.152 (Win Firefox and Mac) (132 MB) (though I believe any recent MAC version should do, this just worked for me)
Step 3: Install the Flash player from Step 2.
Step 4: Download and install the latest version of Adobe Flash Player (that wouldn't initially work)
Step 5: Problem should be solved. You're just reverting your update and re-installing it to fix it.
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