Adding a Union to a transformation gets unhandled event loop exception (NPE)

I added a UNION of two AUTHORS tables to a transformation and got this:

Error 2010-10-28 12:52:34.203 Unhandled event loop exception
java.lang.NullPointerException
at org.teiid.query.sql.lang.SetQuery.clone(SetQuery.java:172)
at com.metamatrix.modeler.internal.transformation.util.TransformationSqlHelper.createSetQueryAddUnionSources(TransformationSqlHelper.java:795)
at com.metamatrix.modeler.internal.transformation.util.TransformationSqlHelper.updateUnionSelectOnGroupsAdded(TransformationSqlHelper.java:392)
at com.metamatrix.modeler.transformation.ui.actions.TransformationSourceManager.addUnionSources(TransformationSourceManager.java:585)
at com.metamatrix.modeler.transformation.ui.actions.AddUnionSourceAction.doRun(AddUnionSourceAction.java:136)
at com.metamatrix.ui.actions.AbstractAction$1.run(AbstractAction.java:537)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at com.metamatrix.ui.actions.AbstractAction.run(AbstractAction.java:540)
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$6.handleEvent(ActionContributionItem.java:452)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604)
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)