Fox-
I should have thought of the debug sooner

. Included in the layout.zip you downloaded there is a presets folder. Copy the images like ship.ping into your \attract\modules\extended\animations\particles\presets. I added new art to the preset folder so anything turned on in the layout will look here. Here is where you turn on the particle effects art in the layout.nut - As you can see the ship is turned on and I added new art like "disk, bit" that is turned off - These files need to be in the preset folder. There is a default ship.png in the original preset folder that might be called ship too which I just renamed. So, technically it should still work if the name is matched in the preset.nut in the presets folder. Take a look at the preset.nut and you will get a better understanding of what is going on. Then look at the layout nut. You can add your own particles effects this way.
//uncomment others to see them
if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "sparkle" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "snow" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "default" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "test" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "cloudstoon" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "bubbles1" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "arc1" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "invaders" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "cloudstoon2" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "disk" } );
//if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "bit" } );
if (config.enable_particles == "Yes") ExtendedObjects.get("bg").animate({ which = "particles", preset = "ship" } );