This message can appear if you attempt to embed a drawing object inside another object that was not designed to accept the ...

This message can appear if you attempt to embed a drawing object inside another object that was not designed to accept the object.  Drawing objects are generally placed on the main document or within the drawing canvas and not within another drawing object.  By design, it is not possible to embed a drawing object in a callout, comment, footnote, or an endnote.  Attempting to do so will cause this message to display.