Null pointer exception in WDSC v7 user action

Created and tried to use my first user action in WDSC...

I'm getting a NULL pointer exception. The log shows:
!STACK 0
java.lang.NullPointerException
at com.ibm.etools.systems.core.ui.uda.SystemUDActionSubsystem.doCommandSubstitutions(Unknown
Source)
at com.ibm.etools.systems.core.ui.uda.SystemUDActionSubsystem.run(Unknown
Source)
at com.ibm.etools.systems.core.ui.uda.SystemUDAsBaseAction.run(Unknown Source)
at org.eclipse.jface.action.Action.runWithEvent(Unknown Source)
at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(Unknown
Source)
at org.eclipse.jface.action.ActionContributionItem.access$2(Unknown Source)
at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(Unknown
Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
at org.eclipse.ui.internal.Workbench.runEventLoop(Unknown Source)
at org.eclipse.ui.internal.Workbench.runUI(Unknown Source)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Unknown Source)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(Unknown Source)
at org.eclipse.ui.internal.ide.IDEApplication.run(Unknown Source)
at org.eclipse.core.internal.runtime.PlatformActivator$1.run(Unknown Source)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(Unknown
Source)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(Unknown
Source)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(Unknown Source)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(Unknown Source)
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(Unknown Source)
at org.eclipse.core.launcher.Main.basicRun(Unknown Source)
at org.eclipse.core.launcher.Main.run(Unknown Source)
at org.eclipse.core.launcher.Main.main(Unknown Source)

Any thoughts?

Already tried restarting WDSC.

Thanks!
Charles