oo I found something *proud*

quote
var _preLoad = _root.createEmptyMovieClip("_preLoad", 200);
var bg = _pL.createEmptyMovieClip("bg", 1);
unquote

should have been
var _preLoad = _root.createEmptyMovieClip("_preLoad", 200);
var bg = _preLoad.createEmptyMovieClip("bg", 1);

changed pL.createEmptyMovieClip to preLoad.createEmptyMovieClip