MESSAGE: Unhandled event loop exception during blocked modal context.

EXCEPTION STACK TRACE:
org.eclipse.swt.SWTException: Failed to execute runnable (org.eclipse.core.runtime.AssertionFailedException: null argument:)
	at org.eclipse.swt.SWT.error(SWT.java:3884)
	at org.eclipse.swt.SWT.error(SWT.java:3799)
	at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:137)
	at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3855)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3476)
	at org.eclipse.jface.operation.ModalContext$ModalContextThread.block(ModalContext.java:173)
	at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:388)
	at org.eclipse.jface.wizard.WizardDialog.run(WizardDialog.java:944)
	at org.eclipse.wst.server.ui.internal.wizard.TaskWizard.performFinish(TaskWizard.java:221)
	at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:752)
	at org.eclipse.jface.wizard.WizardDialog.buttonPressed(WizardDialog.java:373)
	at org.eclipse.jface.dialogs.Dialog$2.widgetSelected(Dialog.java:624)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:228)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1003)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3880)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3473)
	at org.eclipse.jface.window.Window.runEventLoop(Window.java:825)
	at org.eclipse.jface.window.Window.open(Window.java:801)
	at org.eclipse.wst.server.ui.internal.actions.LaunchWizardAction.run(LaunchWizardAction.java:57)
	at org.eclipse.jface.action.Action.runWithEvent(Action.java:498)
	at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:584)
	at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:501)
	at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:411)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1003)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3880)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3473)
	at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2405)
	at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2369)
	at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2221)
	at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:500)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:493)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:113)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:194)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:368)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
	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.equinox.launcher.Main.invokeFramework(Main.java:559)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1311)
Caused by: org.eclipse.core.runtime.AssertionFailedException: null argument:
	at org.eclipse.core.runtime.Assert.isNotNull(Assert.java:85)
	at org.eclipse.core.runtime.Assert.isNotNull(Assert.java:73)
	at org.eclipse.jface.viewers.AbstractTreeViewer.add(AbstractTreeViewer.java:133)
	at org.eclipse.ui.navigator.CommonViewer.add(CommonViewer.java:305)
	at org.eclipse.jface.viewers.AbstractTreeViewer.add(AbstractTreeViewer.java:664)
	at org.eclipse.wst.server.ui.internal.cnf.ServersView2$9.run(ServersView2.java:279)
	at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
	at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:134)
	... 45 more