Hi All,
On my MII Workbench,I am unable to launch Navigation Editor.
I don't have an issue in opening transactions,web and other content.
Even I am able to open Project Navigation Editor & Link Editor from Workbench Tools,Only Navigation Editor throws error.
A screen grab of the error is given below:

Kindly refer the java console log for the errors.
3/8/16 4:19 PM AWT-EventQueue-0 [DEBUG] - Displaying File null
3/8/16 4:19 PM AWT-EventQueue-0 [DEBUG] - Setting Menu Bar for null
3/8/16 4:19 PM AWT-EventQueue-0 [DEBUG] - DisplayFrame took 13
3/8/16 4:19 PM AWT-EventQueue-0 [DEBUG] - ServerName: null
3/8/16 4:19 PM AWT-EventQueue-0 [DEBUG] - Catalog, Mode=ListFolders&DoStateCheck=true
3/8/16 4:19 PM AWT-EventQueue-0 [DEBUG] - Catalog, Mode=RoleList&NavigationUserSource=MIINavigationRole&&Content-Type=text/xml
3/8/16 4:19 PM AWT-EventQueue-0 [DEBUG] - Catalog, Mode=GetProfileInfo&NavigationRecord=5339&NavigationType=ROLE
3/8/16 4:19 PM AWT-EventQueue-0 [ERROR] - java.lang.NullPointerException
at com.sap.xmii.Illuminator.gui.workbench.components.PathEvaluator.processTree(PathEvaluator.java:58)
at com.sap.xmii.Illuminator.gui.workbench.components.PathEvaluator.processNavigationTree(PathEvaluator.java:46)
at com.sap.xmii.Illuminator.gui.workbench.components.NavigationEditor.createLayoutObjects(NavigationEditor.java:391)
at com.sap.xmii.Illuminator.gui.workbench.components.NavigationEditor.<init>(NavigationEditor.java:249)
at com.sap.xmii.Illuminator.gui.workbench.core.EditorFileInfo.load(EditorFileInfo.java:103)
at com.sap.xmii.Illuminator.gui.workbench.components.actions.actions.EditorPageGeneratorAction.doWork(EditorPageGeneratorAction.java:77)
at com.sap.xmii.Illuminator.gui.workbench.components.actions.actions.IWorkbenchAction.execute(IWorkbenchAction.java:60)
at com.sap.xmii.Illuminator.gui.workbench.components.actions.WorkbenchActionHandler.doAction(WorkbenchActionHandler.java:437)
at com.sap.xmii.Illuminator.gui.workbench.components.actions.WorkbenchActionHandler.doAction(WorkbenchActionHandler.java:138)
at com.sap.xmii.Illuminator.gui.workbench.components.popups.WorkbenchMenuCreator.actionPerformed(WorkbenchMenuCreator.java:887)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.AbstractButton.doClick(Unknown Source)
at com.sap.plaf.frog.FrogMenuItemUI$MouseInputHandler.mouseReleased(FrogMenuItemUI.java:724)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(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)
Thanks in advance.
Vinoth