Box2D Forums

Hello everyone,
i have a problem here related to other posts but the solutions posted there are not working for me and actually i don't think it is exactly the same problem.
I have basically to movies with several worlds inside. Each of these movies' structure is very similar to the demo.
To choose wich movie to play, there is a parent movie that loads each of them accordingly.
The problem is that when I try to get to one of them AFTER having finished with the other, i get an error:
*******
TypeError: Error #1034: Error de conversión forzada: no se puede convertir Box2DAS.Common::V2@4e17cfb1 en Box2DAS.Common.V2.
at wck::BodyShape/circle()[/Users/mariano/Documents/Carpeta Mágica/CA!_2012/programación/RecortableMan/10/wck-lib/wck/BodyShape.as:792]
at shapes::Circle/shapes()[/Users/mariano/Documents/Carpeta Mágica/CA!_2012/programación/RecortableMan/10/wck-lib/shapes/Circle.as:8]
at wck::BodyShape/createBody()[/Users/mariano/Documents/Carpeta Mágica/CA!_2012/programación/RecortableMan/10/wck-lib/wck/BodyShape.as:1263]
at Function/http://adobe.com/AS3/2006/builtin::apply()
at wck::World/doOutsideTimeStep()[/Users/mariano/Documents/Carpeta Mágica/CA!_2012/programación/RecortableMan/10/wck-lib/wck/World.as:271]
at wck::BodyShape/create()[/Users/mariano/Documents/Carpeta Mágica/CA!_2012/programación/RecortableMan/10/wck-lib/wck/BodyShape.as:1192]
at misc::Entity/ensureCreated()[/Users/mariano/Documents/Carpeta Mágica/CA!_2012/programación/RecortableMan/10/wck-lib/misc/Entity.as:50]
at <anonymous>()[/Users/mariano/Documents/Carpeta Mágica/CA!_2012/programación/RecortableMan/10/wck-lib/misc/Entity.as:86]
*******************
This error is longer and applies to many different objects. I have made sure the world is destroyed but i don't know why this is happening. I have tried loading and unloading movies and making them visible and invisible.
Thanks in advance for any clues!