Move your mouse over the objects in the wrl to affect the other frame.

	The red cone writes html directly into the frame.
	The green sphere loads an html file into the frame.
	The blue cube loads an html page containing just a wrl into the frame.
	The purple cylinder loads a wrl file directly into the frame.

In some web browser and vrml plugin combinations the purple cylinder and red cone cause problems. In those cases I think it might be that in order to write to a frame there needs to be a pre-existing html page there. If there is no html there then it silently fails.