3th. gen apple TV with 5.2.1 and mac mini with 10.8.3, only black screen on TV after selecting Apple TV on the airplay icon. how to troubleshoot?

I have a 3th Gen Apple TV and a late 2012 mac mini with IOS 10.8.3

- Connected thru HDMI to an ASUS monitor

- Apple tv connected with wire

- Mac Mini connected wireless.

- I can see the Airplay icon on the screen

- I can select my apple TV on the icon pull-down menu (first time it asked me for apple TV password)

- Once selected, my monitor resolution changes and apple TV goes to a blank screen. On the pull-down menu, my apple TV papears selected and the option "match desktop size to:" is selected for my Apple TV.

Any ideas on how to troubleshoot?

Additional Info:

- I can stream from iTunes music with no problem

- From an Air (on same wireless network) I can mirror my display. And form iPad and iPhone I can stream video and music.