I am not sure is this a bug or not. when a rigidbody has aleady on physicsworld, remove it and then add it as addRigidBodyWithGroup(),
then get error. everybody can test this code clip
mat = new ColorMaterial(0xffdd0c, 0.4);
mat.lights=[_light]
var cube:Basic3dObj = new Basic3dObj();
cube.model = new Cube(mat, 200, 200, 200);
cube.rigidbody = new AWPRigidBody(new AWPBoxShape(200, 200, 200), cube.model, 50);
cube.rigidbody.position = new Vector3D(0, 300, 0);
_view.scene.addChild(cube.model);
_physicsWorld.addRigidBody(cube.rigidbody as AWPRigidBody);
_physicsWorld.removeRigidBody(cube.rigidbody as AWPRigidBody);
_physicsWorld.addRigidBodyWithGroup(cube.rigidbody as AWPRigidBody,1,2); //get error at here!
ps:this error only happen when pull the latest files from git.