Keeping Flash Movie at minimum version?

Hello There,

I have created a movie that has navigation buttons in 1 MC and another MC for Load Movie Function. When a button is pressed in the first MC, it attempts to call Load Movie in a another MC. To do this I have used the following function in the MC that contains my buttons:

_root.content.unloadMovie();
_root.content.loadMovie(“about5.swf”);
stop ();

Problem: I want to export the movie as Flash 4 movie, but not possible because I use this function.

This is the only Flash 4 non-compliant part of my movie. Does any one know an equivalent Flash 4 friendly function?