Using Repast Simphony 2.0 eclipse no longer opens after closing perspective and closing application

Newbie to StackOverflow as a poster, so please let me know if I violate conventions. I have searched the forums, but can't find any help for my problems, so here goes...

I'm using Repast Simphony (2.0 version) and have had a horrible Eclipse crash which means that Eclipse now refuses to open at all. The sequence of events as I remember was this:

1. I noticed that a particular package was no longer showing in the Eclipse Package Explorer perspective window (on the left hand side of the main window.
2. I tried closing and re-opening the perspectives, but no joy.
3. I tried the "close all perspectives" option on the "window" menu, assuming that I could then re-open perspectives from scratch.
4. Couldn't re-open perspectives, so I closed the application.
5. Eclipse will no longer open at all.
6. Checked the log file, has an exception which is copied at the end of the post.

I'd be grateful for any help on how I can get Eclipse opening again, with my projects intact.

!SESSION 2011-07-11 14:24:07.720 -----------------------------------------------
eclipse.buildId=M20100909-0800
java.version=1.6.0_22
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_GB
Command-line arguments:  -os win32 -ws win32 -arch x86

!ENTRY org.eclipse.ui.workbench 4 2 2011-07-11 14:24:11.017
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.ui.workbench".
!STACK 0
java.lang.NullPointerException
at repast.simphony.relogo.ide.ReLogoPerspectiveFactory.createInitialLayout(ReLogoPerspectiveFactory.java:35)
at org.eclipse.ui.internal.Perspective.loadPredefinedPersp(Perspective.java:816)
at org.eclipse.ui.internal.Perspective.createPresentation(Perspective.java:270)
at org.eclipse.ui.internal.Perspective.<init>(Perspective.java:156)
at org.eclipse.ui.internal.tweaklets.Workbench3xImplementation.createPerspective(Workbench3xImplementation.java:55)
at org.eclipse.ui.internal.WorkbenchPage.createPerspective(WorkbenchPage.java:1672)
at org.eclipse.ui.internal.WorkbenchPage.openPerspectiveExtras(WorkbenchPage.java:2486)
at org.eclipse.ui.internal.WorkbenchPage.init(WorkbenchPage.java:2439)
at org.eclipse.ui.internal.WorkbenchPage.<init>(WorkbenchPage.java:563)
at org.eclipse.ui.internal.tweaklets.Workbench3xImplementation.createWorkbenchPage(Workbench3xImplementation.java:39)
at org.eclipse.ui.internal.WorkbenchWindow$19.runWithException(WorkbenchWindow.java:2251)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:134)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4041)
at org.eclipse.swt.widgets.Display.r开发者_StackOverflow中文版eadAndDispatch(Display.java:3660)
at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803)
at org.eclipse.ui.internal.Workbench$31.runWithException(Workbench.java:1567)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:134)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4041)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3660)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2548)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
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:369)
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:619)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
at org.eclipse.equinox.launcher.Main.run(Main.java:1407)

!ENTRY org.eclipse.ui 4 0 2011-07-11 14:24:11.235
!MESSAGE Unhandled event loop exception
!STACK 0
java.lang.NullPointerException
at repast.simphony.relogo.ide.ReLogoPerspectiveFactory.createInitialLayout(ReLogoPerspectiveFactory.java:35)
at org.eclipse.ui.internal.Perspective.loadPredefinedPersp(Perspective.java:816)
at org.eclipse.ui.internal.Perspective.createPresentation(Perspective.java:270)
at org.eclipse.ui.internal.Perspective.<init>(Perspective.java:156)
at org.eclipse.ui.internal.tweaklets.Workbench3xImplementation.createPerspective(Workbench3xImplementation.java:55)
at org.eclipse.ui.internal.WorkbenchPage.createPerspective(WorkbenchPage.java:1672)
at org.eclipse.ui.internal.WorkbenchPage.openPerspectiveExtras(WorkbenchPage.java:2486)
at org.eclipse.ui.internal.WorkbenchPage.init(WorkbenchPage.java:2439)
at org.eclipse.ui.internal.WorkbenchPage.<init>(WorkbenchPage.java:563)
at org.eclipse.ui.internal.tweaklets.Workbench3xImplementation.createWorkbenchPage(Workbench3xImplementation.java:39)
at org.eclipse.ui.internal.WorkbenchWindow.busyOpenPage(WorkbenchWindow.java:768)
at org.eclipse.ui.internal.Workbench$23.runWithException(Workbench.java:1221)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:134)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4041)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3660)
at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803)
at org.eclipse.ui.internal.Workbench$31.runWithException(Workbench.java:1567)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:134)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4041)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3660)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2548)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
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:369)
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:619)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
at org.eclipse.equinox.launcher.Main.run(Main.java:1407)

For me helped moving the Repast Simphony folder /plugins/repast.simphony.relogo.ide_2.0.0 to a secure place, restart eclipse, move the folder back to its original place at /plugins and start eclipse again.

You may try moving /.metadata/plugins/org.eclipse.ui.workbench/workbench.xml to a safe location (just in case) and start Eclipse. The workbench layout should be rebuilt with default settings then.