Adding the "PK_EventHandler" criteria, as I suspect is what you did, does not work as you want it to.
There is no way to check the status of devices (lights on/off, media playing/not playing etc) within the event criteria, so I don't think its possible to set up the event the way you want.
I'm not sure how the timed event got there, but I have an event called "Watching - Home Theater"
PK_EventHandler Event parameter:PK_Room = Home Theater
I havent tried using it, so I'm guessing it's a lost cause? Isn't there a way to poll Xine_plugin to get filename or format etc?