Save Multiple GameObject with XML

I really puzzled with

From this script. how to this script could save / load array of game objects positions ? And how to make the used objects disappear while loading this scene (from loadXML) ?
when i change the _player : GameObject; to _player : GameObject; it happen NullReferenceException: Object reference not set to an instance of an object.

Please i really need this function. Thanks for the answer

Take a Look in the, there have full sources of Unity3D / XML, can be a help.