java.lang.IllegalStateException
        at org.netbeans.modules.kenai.ui.treelist.TreeListNode.addListener(TreeListNode.java:205)
        at org.netbeans.modules.kenai.ui.treelist.TreeListModel.addNodes(TreeListModel.java:212)
        at org.netbeans.modules.kenai.ui.treelist.TreeListModel.addChildrenOf(TreeListModel.java:200)
        at org.netbeans.modules.kenai.ui.treelist.TreeListModel.childrenAdded(TreeListModel.java:226)
        at org.netbeans.modules.kenai.ui.treelist.TreeListNode$ChildrenLoader$2.run(TreeListNode.java:325)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)