Sync Complete, But Won't Play

The synchronization is complete except for Carol of the Bells. I connected the MP3 controller, downloaded the show, but only the first song plays and the lights do not turn on. I hope the MP3 controller isn't bad. I've tried various things, but no luck. I suspect a problem with the sync cable between the Monster Brain and the MP3 controller. It's the only thing that I'm not sure is connected correctly. It has two wires, but three pins to connect to. I can't work on this any more tonight so I'll continue tomorrow. I have to figure this out to meet the contest deadline. I'm also having coworkers stop by Friday to see the show.