Cause the paths are relative to the root url that you might have not setup correctly ???
The code should look like this :
BABYLON.SceneLoader.ImportMesh("", “https://playground.babylonjs.com/scenes/”, “dude.babylon”, scene, function (newMeshes) {
// Set the target of the camera to the first imported mesh
camera.target = newMeshes[0];
});
to ensure the assets loads relatively to https://playground.babylonjs.com/scenes/