Dave,
  I experience the same problem recently.  After much head scratching
etc, I realize that I was in a Morphic World.  MVC is not used in this
world so ScheduledControllers is nil.  You need to open up an MVC project
and do your work..  Then ScheduledControllers will have a proper value
and function properly.
Happy OOPs!
Phil

Dave Newman wrote:

> Hello,
>
> I was creating a little UI that wanted to use MVC, specifically
> PluggableListView. I went to execute some samples that used MVC and
> they all hit the wall when a message was sent to the controller
> residing in the system pool under ScheduledControllers. I found that
> ScheduledControllers was set to nil.
>
> I have not run the slim-down-Squeak code that removes MVC from my
> Squeak image, so I'm at a loss as to how the ScheduledControllers was
> sit to nil in the system pool. However, my real question is what
> measure should I take to restore this to a sensible object other than
> nil?
>
> Thanks,
>
> Dave Newman