here is the log
<pre>

!ENTRY org.eclipse.ui.workbench 4 2 2007-01-16 09:44:06.218
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.ui.workbench".
!STACK 0
java.lang.NoSuchMethodError: org.eclipse.jface.viewers.TreeViewer.setComparator(Lorg/eclipse/jface/viewers/ViewerComparator;)V
	at ch.epfl.lamp.sdt.ui.scalaeditor.ScalaContentOutline.createControl(ScalaContentOutline.java:42)
	at org.eclipse.ui.views.contentoutline.ContentOutline.doCreatePage(ContentOutline.java:133)
	at org.eclipse.ui.part.PageBookView.createPage(PageBookView.java:393)
	at org.eclipse.ui.part.PageBookView.partActivated(PageBookView.java:731)
	at org.eclipse.ui.internal.PartListenerList$1.run(PartListenerList.java:71)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
	at org.eclipse.core.runtime.Platform.run(Platform.java:816)
	at org.eclipse.ui.internal.PartListenerList.fireEvent(PartListenerList.java:57)
	at org.eclipse.ui.internal.PartListenerList.firePartActivated(PartListenerList.java:69)
	at org.eclipse.ui.internal.PartService.firePartActivated(PartService.java:73)
	at org.eclipse.ui.internal.PartService.setActivePart(PartService.java:171)
	at org.eclipse.ui.internal.WorkbenchPagePartList.fireActivePartChanged(WorkbenchPagePartList.java:56)
	at org.eclipse.ui.internal.PartList.setActivePart(PartList.java:117)
	at org.eclipse.ui.internal.WorkbenchPage.setActivePart(WorkbenchPage.java:2975)
	at org.eclipse.ui.internal.WorkbenchPage.activate(WorkbenchPage.java:555)
	at org.eclipse.ui.views.markers.internal.ActionOpenMarker.run(ActionOpenMarker.java:68)
	at org.eclipse.ui.views.markers.internal.MarkerView.handleOpenEvent(MarkerView.java:985)
	at org.eclipse.ui.views.markers.internal.TableView$2.open(TableView.java:165)
	at org.eclipse.jface.viewers.StructuredViewer$2.run(StructuredViewer.java:780)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
	at org.eclipse.core.runtime.Platform.run(Platform.java:816)
	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:778)
	at org.eclipse.jface.viewers.StructuredViewer.handleOpen(StructuredViewer.java:1009)
	at org.eclipse.jface.viewers.StructuredViewer$6.handleOpen(StructuredViewer.java:1108)
	at org.eclipse.jface.util.OpenStrategy.fireOpenEvent(OpenStrategy.java:244)
	at org.eclipse.jface.util.OpenStrategy.access$2(OpenStrategy.java:239)
	at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:278)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:925)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3287)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2907)
	at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:1899)
	at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1863)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:417)
	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:99)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:92)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:68)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:374)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:169)
	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.main(Main.java:952)
</pre>