Why is DVD Player app 'grey' and not functioning on my macbook air / mavericks 10.9.1 ?

Thanks for your reply. I use Screen Sharing too. But the DVD player does not work even if Screen Sharing is turned off on all computers.

Thanks for your response. But changing the display settings didn't solve the problem.

No improvement, the DVD player is still grey 😟

Thank you! I couldn't find anyone else with a similar set up until now. It helps me with one iMac, but any solutions yet for how to work with display link?