Kepler

I searched sdf director and got it on the left panel. Then I tried to drag it to the canvas, but i got the exception:
com.microstar.xml.XmlException: Cannot create entity without a class name. in [external stream] at line 2 and column 22
at ptolemy.moml.MoMLParser._checkForNull(MoMLParser.java:3992)
at ptolemy.moml.MoMLParser._createEntity(MoMLParser.java:4173)
at ptolemy.moml.MoMLParser.startElement(MoMLParser.java:2694)
at com.microstar.xml.XmlParser.parseElement(XmlParser.java:922)
at com.microstar.xml.XmlParser.parseContent(XmlParser.java:1105)
at com.microstar.xml.XmlParser.parseElement(XmlParser.java:925)
at com.microstar.xml.XmlParser.parseContent(XmlParser.java:1105)
at com.microstar.xml.XmlParser.parseElement(XmlParser.java:925)
at com.microstar.xml.XmlParser.parseDocument(XmlParser.java:481)
at com.microstar.xml.XmlParser.doParse(XmlParser.java:159)
at com.microstar.xml.XmlParser.parse(XmlParser.java:132)
at ptolemy.moml.MoMLParser.parse(MoMLParser.java:1538)
at ptolemy.moml.MoMLParser.parse(MoMLParser.java:1510)
at ptolemy.moml.MoMLParser.parse(MoMLParser.java:1666)
at ptolemy.moml.MoMLChangeRequest._execute(MoMLChangeRequest.java:289)
at ptolemy.kernel.util.ChangeRequest.execute(ChangeRequest.java:171)
at ptolemy.kernel.util.NamedObj.executeChangeRequests(NamedObj.java:738)
at ptolemy.kernel.util.NamedObj.requestChange(NamedObj.java:1778)
at ptolemy.actor.CompositeActor.requestChange(CompositeActor.java:1922)
at ptolemy.vergil.basic.EditorDropTargetListener.drop(EditorDropTargetListener.java:369)
at java.awt.dnd.DropTarget.drop(DropTarget.java:430)
at sun.awt.dnd.SunDropTargetContextPeer.processDropMessage(SunDropTargetContextPeer.java:500)
at sun.awt.X11.XDropTargetContextPeer.processDropMessage(XDropTargetContextPeer.java:165)
at sun.awt.dnd.SunDropTargetContextPeer$EventDispatcher.dispatchDropEvent(SunDropTargetContextPeer.java:812)
at sun.awt.dnd.SunDropTargetContextPeer$EventDispatcher.dispatchEvent(SunDropTargetContextPeer.java:736)
at sun.awt.dnd.SunDropTargetEvent.dispatch(SunDropTargetEvent.java:30)
at java.awt.Component.dispatchEventImpl(Component.java:4270)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Component.dispatchEvent(Component.java:4243)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)
at java.awt.LightweightDispatcher.processDropTargetEvent(Container.java:4057)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3911)
at java.awt.Container.dispatchEventImpl(Container.java:2102)
at java.awt.Window.dispatchEventImpl(Window.java:2440)
at java.awt.Component.dispatchEvent(Component.java:4243)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)