I had a similar issue. I added a comma to the end of the line “sounds:”

            {
                    module: "MMM-EasyPix",
                    position: "middle_center",
                    config: {
                            picName: "DSC01423.JPG",             // Enter the picture file name.
                            maxWidth: "75%",                     // Size picture precisely. Retains aspect ratio.
                            sounds: ["1.mp3", "me2.mp3"],         // mp3 sound file names in quotes seperated by commas for Hello-Lucy
                            updateInterval: 30 * 60 * 1000,      // updates display
                            animationSpeed: 3000,
                    }
            },

Hope this helps

Would love to know how to have a slide show without having to create a list in the config.js file.