How can I insert a video *.mp4? I tried in several ways

I work with windows 8, installed the latest version of adobe flashplayer:

install_flashplayer17x32pp_mssd_aaa_aih.exe, restart my computer.

I not upload the website, just  look with the peview and become again th error as you see in the attached file.

I also tried it with the link to youtube: 

https://www.youtube.com/watch?v=Dua7mFQKL9Q

The same error message.