Something in the registry didn't update when the Player did. You can disable update notifications in your Flash Player Global Settings (accessible by right clicking any Flash content). Under the Advanced tab, simply check the third option, "Never check for updates". The only drawback is that when a new release comes out, you'll have to download it manually or through the Global Settings updater, as it won't happen automatically anymore.
Or it may be fake update notifications (malware). Can you post a screenshot of such a notification?