java.lang.NullPointerException
   at org.netbeans.modules.erd.io.DocumentLoad.getChildNode(DocumentLoad.java:179)
   at org.netbeans.modules.erd.io.DocumentLoad.load(DocumentLoad.java:84)
   at org.netbeans.modules.erd.model.DocumentSerializer$1.run(DocumentSerializer.java:78)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1432)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2042)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.NullPointerException
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:424)
   at org.netbeans.modules.erd.model.DocumentSerializer.startLoadingDocument(DocumentSerializer.java:112)
   at org.netbeans.modules.erd.editor.ERDTopComponent.componentOpened(ERDTopComponent.java:123)
   at org.openide.windows.WindowManager.componentOpenNotify(WindowManager.java:307)
   at org.netbeans.core.windows.WindowManagerImpl.notifyTopComponentOpened(WindowManagerImpl.java:1140)
   at org.netbeans.core.windows.Central.addModeOpenedTopComponent(Central.java:798)
   at org.netbeans.core.windows.ModeImpl.addOpenedTopComponent(ModeImpl.java:354)
   at org.netbeans.core.windows.WindowManagerImpl.topComponentOpenAtTabPosition(WindowManagerImpl.java:1252)
   at org.netbeans.core.windows.WindowManagerImpl.topComponentOpen(WindowManagerImpl.java:1217)
   at org.openide.windows.TopComponent.open(TopComponent.java:497)
   at org.openide.windows.TopComponent.open(TopComponent.java:477)
   at org.openide.windows.CloneableOpenSupport.openCloneableTopComponent(CloneableOpenSupport.java:202)
   at org.openide.windows.CloneableOpenSupport$1.run(CloneableOpenSupport.java:101)
   at org.openide.util.Mutex.doEvent(Mutex.java:1343)
   at org.openide.util.Mutex.writeAccess(Mutex.java:457)
   at org.openide.windows.CloneableOpenSupport.open(CloneableOpenSupport.java:98)
   at org.netbeans.modules.erd.editor.ERDEditorSupport.open(ERDEditorSupport.java:136)
   at org.netbeans.modules.erd.actions.ViewDiagramOnConnection.openDiagram(ViewDiagramOnConnection.java:105)
   at org.netbeans.modules.erd.actions.ViewDiagramOnConnection.actionPerformed(ViewDiagramOnConnection.java:77)
   at org.openide.awt.InjectorExactlyOne.actionPerformed(InjectorExactlyOne.java:78)
   at org.openide.awt.ContextAction$Performer.actionPerformed(ContextAction.java:226)
   at org.openide.awt.ContextManager.actionPerformed(ContextManager.java:257)
   at org.openide.awt.ContextAction.actionPerformed(ContextAction.java:109)
   at org.openide.util.actions.ActionInvoker$1.run(ActionInvoker.java:93)
   at org.openide.util.actions.ActionInvoker.doPerformAction(ActionInvoker.java:116)
   at org.openide.util.actions.ActionInvoker.invokeAction(ActionInvoker.java:99)
   at org.openide.awt.GeneralAction$BaseDelAction.actionPerformed(GeneralAction.java:234)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
   at javax.swing.AbstractButton.doClick(AbstractButton.java:376)
   at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)
   at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)
   at java.awt.Component.processMouseEvent(Component.java:6505)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
   at java.awt.Component.processEvent(Component.java:6270)
   at java.awt.Container.processEvent(Container.java:2229)
   at java.awt.Component.dispatchEventImpl(Component.java:4861)
   at java.awt.Container.dispatchEventImpl(Container.java:2287)
   at java.awt.Component.dispatchEvent(Component.java:4687)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4832)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4492)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4422)
   at java.awt.Container.dispatchEventImpl(Container.java:2273)
   at java.awt.Window.dispatchEventImpl(Window.java:2719)
   at java.awt.Component.dispatchEvent(Component.java:4687)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:729)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:688)
   at java.awt.EventQueue$3.run(EventQueue.java:686)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
   at java.awt.EventQueue$4.run(EventQueue.java:702)
   at java.awt.EventQueue$4.run(EventQueue.java:700)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:699)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)