_parent or _root calls not working?

Actually I’ve got two problems, but the parent root one first:
My ‘main.swf’ has this code in first frame

[AS]
_root.createEmptyMovieClip(“holder1”, 1);
loadMovie(“main_menu.swf”, “holder1”);
holder1._x = 10 ;
holder1._y = 10 ;
_root.createEmptyMovieClip(“holder2”, 2);
loadMovie(“intro_left.jpg”, “holder2”);
holder2._x = 10 ;
holder2._y = 320 ;

[/AS]

All the way upto ‘holder5.’ It all loads great so far. One of the external movies that gets loaded is my main menu, and i want to make it so that when i click on the buttons in the loaded ‘main_menu.swf’ it will loadMovie the intended movie onto the corresponding emptyclip in the root ‘main.swf.’ Basically I’ve tried copying the same code above onto the code for the ‘on (release)’ of the button in the ‘main_menu.swf’, except altering the path’s of the loaded movies to the correct newly loaded movie. But the screen goes white, and nothing loads.

.