java.lang.NullPointerException: This exception has no message.

java.lang.NullPointerException: 	at org.eclipse.ui.part.MultiPageEditorPart.pageChange(MultiPageEditorPart.java:511)	at com.m7.wide.eclipse.jstudio.DynamicMultiPageEditor.pageChange(Unknown Source)	at com.m7.wide.eclipse.jstudio.DynamicMultiPageEditor.pageChange(Unknown Source)	at org.eclipse.ui.part.MultiPageEditorPart.setActivePage(MultiPageEditorPart.java:580)	at com.m7.wide.eclipse.jstudio.DynamicMultiPageEditor.createPages(Unknown Source)	at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:241)	at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:598)	at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:374)	at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:552)	at org.eclipse.ui.internal.EditorReference.getEditor(EditorReference.java:213)	at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditorBatched(WorkbenchPage.java:2382)	at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:2315)	at org.eclipse.ui.internal.WorkbenchPage.access$10(WorkbenchPage.java:2307)	at org.eclipse.ui.internal.WorkbenchPage$9.run(WorkbenchPage.java:2293)	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:69)	at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2288)	at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2269)	at org.eclipse.ui.ide.IDE.openEditor(IDE.java:754)	at org.eclipse.ui.ide.IDE.openEditor(IDE.java:698)	at com.m7.wide.eclipse.Eclipse3WideEnv.openEditor(Unknown Source)	at com.m7.wide.eclipse.EclipseWideEnv.openEditor(Unknown Source)	at com.m7.wide.project.artifact.action.OpenAction.run(Unknown Source)	at com.m7.wide.eclipse.jstudio.appexplorer.AppExplorerTreeViewer.open(Unknown Source)	at org.eclipse.jface.viewers.StructuredViewer$2.run(StructuredViewer.java:741)	at org.eclipse.core.internal.runtime.InternalPlatform.run(InternalPlatform.java:1044)	at org.eclipse.core.runtime.Platform.run(Platform.java:783)	at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:44)	at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:148)	at org.eclipse.jface.viewers.StructuredViewer.fireOpen(StructuredViewer.java:739)	at org.eclipse.jface.viewers.StructuredViewer.handleOpen(StructuredViewer.java:968)	at org.eclipse.jface.viewers.StructuredViewer$6.handleOpen(StructuredViewer.java:1067)	at org.eclipse.jface.util.OpenStrategy.fireOpenEvent(OpenStrategy.java:243)	at org.eclipse.jface.util.OpenStrategy.access$2(OpenStrategy.java:238)	at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:277)	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:896)	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3236)	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2856)	at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:1774)	at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1738)	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:376)	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:143)	at org.eclipse.ui.internal.ide.IDEApplication.run(IDEApplication.java:106)	at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:226)	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:376)	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:165)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)	at java.lang.reflect.Method.invoke(Unknown Source)	at org.eclipse.core.launcher.Main.invokeFramework(Main.java:338)	at org.eclipse.core.launcher.Main.basicRun(Main.java:282)	at org.eclipse.core.launcher.Main.run(Main.java:977)	at org.eclipse.core.launcher.Main.eclipse_main(Main.java:952)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)	at java.lang.reflect.Method.invoke(Unknown Source)	at com.m7.installer.util.NitroxMain$1.run(NitroxMain.java:29)	at java.awt.event.InvocationEvent.dispatch(Unknown Source)	at java.awt.EventQueue.dispatchEvent(Unknown Source)	at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)	at java.awt.EventDispatchThread.run(Unknown Source)