Flash Player wouldn't update on Safari 6.1.6 - Critical Issues??

Cannot play Youtube videos and I need to update my flash player - simple! BUT on try to initializing the Adobe update the progress would fail leaving me with a black window and ultimately failing to update my Flash Player?

On my Safari Preferences > Security > Manage Web Settings I am faced with a warning stating "The known version of Adobe Flash Player has known critical issues"

I've now set Adobe Flash Player the 'Allow Always' so I can access Youtube video but is something extremely wrong with my software with Mac/Safair or Adobe and is it safe to set security preferences to Allow Always? Please see inserted picture below.

I'm running Lion 10.7.5 Safari 6.1.6, thank you