Flash Player failure in Safari e Firefox, not Chrome

Hi,

I'm having this problem with Flash Plugin on Safari (my default browser) and Firefox,

but not on Chrome (never used before, just to check if all the browsers were failing or not).

I have try all the preferencies in Safari and Flash setting.

Also re-installed 3/4 times the Flash Player from Adobe.

Eventually, I installed new OS Mavericks, but the problem is still there, Error Plugin on both browsers.

Anyone can help or suggest something?

Thank you in advance!!