I get an error that says "Uncaught Exception in thread 'AWT-EventQueue-1' " when I try to open "Attribute" in "User Dialog Event"

This is the Error Report :

--- Stack Trace ---
java.lang.NullPointerException
  at ch.ivyteam.awtExt.treetable.TreeTableRenderer.getNode(TreeTableRenderer.java:272)
  at ch.ivyteam.ivy.awtGuiComponents.ivvScriptTrees.IvyScriptTreeTableCellRenderer.getTableCellRendererComponent(IvyScriptTreeTableCellRenderer.java:106)
  at javax.swing.JTable$AccessibleJTable.getAccessibleChild(JTable.java:7037)
  at javax.swing.JTable$AccessibleJTable.getAccessibleAt(JTable.java:7424)
  at javax.swing.JTable$AccessibleJTable.valueChanged(JTable.java:6939)
  at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:184)
  at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:164)
  at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:211)
  at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:405)
  at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:415)
  at javax.swing.DefaultListSelectionModel.removeSelectionIntervalImpl(DefaultListSelectionModel.java:576)
  at javax.swing.DefaultListSelectionModel.clearSelection(DefaultListSelectionModel.java:420)
  at javax.swing.JTable.clearSelection(JTable.java:2120)
  at javax.swing.JTable.clearSelectionAndLeadAnchor(JTable.java:2128)
  at javax.swing.JTable.tableChanged(JTable.java:4451)
  at ch.ivyteam.awtExt.treetable.VariableRowHeightTreeTable.tableChanged(VariableRowHeightTreeTable.java:44)
  at ch.ivyteam.awtExt.treetable.InternalModel.computeVisibleRows(InternalModel.java:645)
  at ch.ivyteam.awtExt.treetable.InternalModel.expandOrCollapse(InternalModel.java:428)
  at ch.ivyteam.awtExt.treetable.FilteredInternalModel.filterExpandOrCollapse(FilteredInternalModel.java:202)
  at ch.ivyteam.awtExt.treetable.BaseMapModelFilter.filterExpandOrCollapse(BaseMapModelFilter.java:123)
  at ch.ivyteam.awtExt.treetable.FilteredInternalModel.expandOrCollapse(FilteredInternalModel.java:67)
  at ch.ivyteam.awtExt.treetable.TreeTable$1.mouseClicked(TreeTable.java:94)
  at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:270)
  at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:269)
  at java.awt.Component.processMouseEvent(Component.java:6542)
  at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
  at java.awt.Component.processEvent(Component.java:6304)
  at java.awt.Container.processEvent(Container.java:2239)
  at java.awt.Component.dispatchEventImpl(Component.java:4889)
  at java.awt.Container.dispatchEventImpl(Container.java:2297)
  at java.awt.Component.dispatchEvent(Component.java:4711)
  at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4904)
  at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4544)
  at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4476)
  at java.awt.Container.dispatchEventImpl(Container.java:2283)
  at java.awt.Component.dispatchEvent(Component.java:4711)
  at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
  at java.awt.EventQueue.access$500(EventQueue.java:97)
  at java.awt.EventQueue$3.run(EventQueue.java:709)
  at java.awt.EventQueue$3.run(EventQueue.java:703)
  at java.security.AccessController.doPrivileged(Native Method)
  at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
  at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
  at java.awt.EventQueue$4.run(EventQueue.java:733)
  at java.awt.EventQueue$4.run(EventQueue.java:731)
  at java.security.AccessController.doPrivileged(Native Method)
  at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
  at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
  at org.GNOME.Accessibility.AtkWrapper$6.dispatchEvent(AtkWrapper.java:715)
  at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
  at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
  at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
  at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
  at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
  at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)