java.lang.NullPointerException in Operation Behavior

I have a project (this works OK on other projects, just one that it fails on) that causes RTC to give:

An error has occurred. See error log for more details.
java.lang.NullPointerException

whenever I try to add the Operation Behavior "Prevent Editing" in the project area editor. It seems be trying to display the "Prevent changes for the following states:" window at that time. It doesn't have this problem on adding other preconditions.

Has anyone else run into this issue and have a work-around to avoid it?

Here is the error log:

Message: Problems occurred when invoking code from plug-in: "org.eclipse.jface".

Exception Stack Trace:
java.lang.NullPointerException
at com.ibm.team.workitem.ide.ui.internal.aspecteditor.teamoperation.StateBasedModificationEditor.getResolutions(StateBasedModificationEditor.java:396)
at com.ibm.team.workitem.ide.ui.internal.aspecteditor.teamoperation.StateBasedModificationEditor.buildTree(StateBasedModificationEditor.java:377)
at com.ibm.team.workitem.ide.ui.internal.aspecteditor.teamoperation.StateBasedModificationEditor.init(StateBasedModificationEditor.java:220)
at com.ibm.team.workitem.ide.ui.internal.aspecteditor.teamoperation.StateBasedModificationEditor.createControl(StateBasedModificationEditor.java:216)
at com.ibm.team.process.internal.ide.ui.editors.form.OperationsAspectEditor.showDetailEditor(OperationsAspectEditor.java:541)
at com.ibm.team.process.internal.ide.ui.editors.form.OperationsAspectEditor.updateDetails(OperationsAspectEditor.java:484)
at com.ibm.team.process.internal.ide.ui.editors.form.OperationsAspectEditor.handleDetailAspectSelection(OperationsAspectEditor.java:901)
at com.ibm.team.process.internal.ide.ui.editors.form.OperationsAspectEditor.access$14(OperationsAspectEditor.java:891)
at com.ibm.team.process.internal.ide.ui.editors.form.OperationsAspectEditor$12.selectionChanged(OperationsAspectEditor.java:715)
at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:162)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.runtime.Platform.run(Platform.java:880)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:48)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:160)
at org.eclipse.jface.viewers.StructuredViewer.updateSelection(StructuredViewer.java:2062)
at org.eclipse.jface.viewers.StructuredViewer.handleSelect(StructuredViewer.java:1138)
at org.eclipse.jface.viewers.StructuredViewer$4.widgetSelected(StructuredViewer.java:1168)
at org.eclipse.jface.util.OpenStrategy.fireSelectionEvent(OpenStrategy.java:227)
at org.eclipse.jface.util.OpenStrategy.access$3(OpenStrategy.java:221)
at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:388)
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:3840)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3439)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2384)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2348)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2200)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:495)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:288)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:490)
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:193)
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:386)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:79)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:618)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:549)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:504)
at org.eclipse.equinox.launcher.Main.run(Main.java:1236)

Session Data:
eclipse.buildId=I20100602-1000
java.fullversion=J2RE 1.5.0 IBM J9 2.3 Windows XP x86-32 j9vmwi3223-20091104 (JIT enabled)
J9VM - 20091103_45935_lHdSMr
JIT - 20091016_1845_r8
GC - 20091026_AA
BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_US
Command-line arguments: -os win32 -ws win32 -arch x86