When I try Gecko OS with AC: CF I get an error that there's no DVD in the system. The system knows that there is one (it says on the DVD channel) yet it doesn't do anything.
Just eject and reinsert until it works. I used to have that issue, then my drive went completely bad a week after, and then i got a new one, never again has it happened :|
Looks like you're screwed.
For the time being you can just insert til it works