Binary Exporter and Importer

Im having some trouble getting saving and loading working. I just have a simple app with a single box with a material on it. Binary exporting seems to work fine but when i try to load it using the binary importer, i get an error message.

SEVERE BinaryClassLoader 4:16:35 AM Could not access constructor of class 'com.jme3.scene.shape.Box'!
Some types need to have the BinaryImporter set up in a special way. Please doublecheck the setup.

What does this mean?

Heres my loading code:

                      FileInputStream is = new FileInputStream(fc.getSelectedFile());
            // Laden der abgespeicherte Szene als Node
            Node loadedNode = (Node) BinaryImporter.getInstance().load(is);
            // Erstelle eine ArrayList und fuege alle Children des Nodes dieser Liste hinzu
            ArrayList<Spatial> allspat = new ArrayList<Spatial>();

            // Durchlaufe die ArrayList und hange jedes darin vorkommende "Spatial" der "sceneNode" an;
            // Wie wir wissen sollte es sich bei den vorkommenden Spatials nur um 2 Knoten handeln:
            // geometryNode, lightNode
            for(Spatial s:allspat)

The reason this happens is because the Box class does not have an empty constructor, which is required for serialization.

I have fixed this issue in the latest revision, update from SVN.