error when trying to use in eclipse 3.2.1

Using Eclipse 3.2.1, JadClipse 3.2.4, and JAD 1.5.8g, fresh Eclipse install, new Java project, imported file tree that contains only .class files, get:

"Unable to create this part due to an internal error. Reason for the failure: Operation not supported for specified element type(s):<project root>"

Java Model Exception: Java Model Status [Operation not supported for specified element type(s):<project root> [in cdf-3.11.1]]
at org.eclipse.jdt.internal.core.ClassFile.getBuffer(ClassFile.java:315)
at org.eclipse.jdt.internal.core.ClassFile.getSourceRange(ClassFile.java:465)
at org.eclipse.jdt.internal.ui.javaeditor.ClassFileEditor.probeInputForSource(ClassFileEditor.java:681)
at org.eclipse.jdt.internal.ui.javaeditor.ClassFileEditor.doSetInput(ClassFileEditor.java:610)
at org.eclipse.ui.texteditor.AbstractTextEditor$17.run(AbstractTextEditor.java:2396)
at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:369)
at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:313)
at org.eclipse.jface.window.ApplicationWindow$1.run(ApplicationWindow.java:763)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:67)
at org.eclipse.jface.window.ApplicationWindow.run(ApplicationWindow.java:760)
at org.eclipse.ui.internal.WorkbenchWindow.run(WorkbenchWindow.java:2283)
at org.eclipse.ui.texteditor.AbstractTextEditor.internalInit(AbstractTextEditor.java:2414)
at org.eclipse.ui.texteditor.AbstractTextEditor.init(AbstractTextEditor.java:2441)
at org.eclipse.ui.internal.EditorManager.createSite(EditorManager.java:840)
at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:583)
at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:372)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:566)
at org.eclipse.ui.internal.EditorReference.getEditor(EditorReference.java:214)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditorBatched(WorkbenchPage.java:2595)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:2528)
at org.eclipse.ui.internal.WorkbenchPage.access$10(WorkbenchPage.java:2520)
at org.eclipse.ui.internal.WorkbenchPage$9.run(WorkbenchPage.java:2505)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:67)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2500)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2485)
at org.eclipse.ui.ide.IDE.openEditor(IDE.java:388)
at org.eclipse.ui.ide.IDE.openEditor(IDE.java:350)
at org.eclipse.ui.actions.OpenFileAction.openFile(OpenFileAction.java:98)
at org.eclipse.ui.actions.OpenSystemEditorAction.run(OpenSystemEditorAction.java:98)
at org.eclipse.ui.views.navigator.OpenActionGroup.runDefaultAction(OpenActionGroup.java:125)
at org.eclipse.ui.views.navigator.MainActionGroup.runDefaultAction(MainActionGroup.java:328)
at org.eclipse.ui.views.navigator.ResourceNavigator.handleOpen(ResourceNavigator.java:679)
at org.eclipse.ui.views.navigator.ResourceNavigator$6.open(ResourceNavigator.java:434)
at org.eclipse.jface.viewers.StructuredViewer$2.run(StructuredViewer.java:817)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.runtime.Platform.run(Platform.java:843)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:44)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:149)
at org.eclipse.jface.viewers.StructuredViewer.fireOpen(StructuredViewer.java:815)
at org.eclipse.jface.viewers.StructuredViewer.handleOpen(StructuredViewer.java:1069)
at org.eclipse.jface.viewers.StructuredViewer$6.handleOpen(StructuredViewer.java:1168)
at org.eclipse.jface.util.OpenStrategy.fireOpenEvent(OpenStrategy.java:249)
at org.eclipse.jface.util.OpenStrategy.access$2(OpenStrategy.java:243)
at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:283)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:928)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3348)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2968)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:1914)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1878)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:419)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.IDEApplication.run(IDEApplication.java:95)
at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:78)
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:400)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:177)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.eclipse.core.launcher.Main.invokeFramework(Main.java:336)
at org.eclipse.core.launcher.Main.basicRun(Main.java:280)
at org.eclipse.core.launcher.Main.run(Main.java:977)
at org.eclipse.core.launcher.Main.main(Main.java:952)