How to replace TOKAMAK objects

Hi,

I've got an array of actors, of custom type including fields for 3D geometry, TOKAMAK RB, and position/orientation/properties etc. I load this array with details describing each object (actor) and use two functions that create the 3D Blitz entities and the TOK RB's from the information in the array...

actors(n)\model = create_actor_geometry(actors(n))
actors(n)\TOK_obj = create_actor_TOK_object(actors(n))

I can clear the whole scene with this code...

For n=1 To NUM_ACTORS
		FreeEntity (actors(n)\model)
		actors(n)\visible=False
		TOKRB_Free (actors(n)\TOK_obj)
	Next

and load in objects in the same manner I initialise them, which works fine.

What I cannot do though is use this method to erase ONE tokamak object and replace it with another.

	FreeEntity (actors(n)\model)
	actors(n)\visible=False
	TOKRB_Free (actors(n)\TOK_obj)

	actors(n)\model = create_actor_geometry(actors(n))
	actors(n)\TOK_obj = create_actor_TOK_object(actors(n))

The results are erratic. The new object is created and updates as before, but collision is broken. The object responds to some TOX_ABs and TOK_RBs, and then passes through others. If I replace the object 2 or 3 times, I get a "Memory Access Violation" on the TOKSIM_Advance() function

Does anyone know what's causing this, or how I can replace one TOKAMAK object with another?

Note : I am advancing the simulation between calls to TOKRB_Free()