The latest Flash version is needed, so first, you can go here to verify you have the latest Flash version:  http://manage.voxwire.com/systemcheck/

 

Otherwise if there is a Flash error, while in the room right-click to bring up the Flash controls, choose the webcam icon if that is the error, or the microphone icon if a mic error, and in each use the drop-down menu to select the specific product you have (rather than the default of auto-select).