"Variable addChild is not defined."

I’ve got a utility function to load swfs. It places a progress bar onscreen for user feedback: “marker = addChild (new Preloader).”

When I migrated the function to an external class:

public static function loadFile (…) {
marker = addChild (new Preloader).

I get an error “Variable addChild is not defined.”

I’m guessing this is a context issue–how does flash know what to attach the new child to?