Error #1056: Cannot create property __id0_ on ModuleSwf

Question

I have a document class for a SWF. This SWF compiles and runs fine.  When I load it inside another SWF, I get this:
ReferenceError: Error #1056: Cannot create property __id0_ on ModuleSwf.
          at flash.display::Sprite/constructChildren()
          at flash.display::Sprite()
          at flash.display::MovieClip()
          at ModuleSwf()
ModuleSwf is the document class of the loaded SWF.  What is causing this?

Answer 1

ReferenceError: Error #1056: Cannot create property __id0_ on ModuleSwf.
          at flash.display::Sprite/constructChildren()
          at flash.display::Sprite()
          at flash.display::MovieClip()
          at ModuleSwf()[C:\Users\me\Projects\MyProject\Production\Assembly\classes\ModuleSwf.as:17]
package
          import flash.display.DisplayObject;
          import flash.display.MovieClip;
          import flash.events.Event;
          public class ModuleSwf extends MovieClip
          {   // This is line 17
            public function ModuleSwf()
                              if (this != root)
                                        stop();
                              addEventListener(Event.ADDED_TO_STAGE, addedToStageHandler, false, 0, true);
                              addEventListener(Event.REMOVED_FROM_STAGE, removedFromStageHandler, false, 0, true);