Parts of the parent movie not completely loaded

I have been getting errors when i try and make a call or get data from something on the main stage (like a volume slider) from an external class.

Its so annoying.

I have flash gallery with an mp3 component. The MP3 component features a volume slider movie clip that i manually put on the stage.

When i try and reference this from a file that is not the main as3 file it comes back as not being defined unless i set a small timer to kind of put my external class to sleep, then reference the slider.

Is there a better way of doing this… Is there a way to fire off an event when all the components on the main stage are fully loaded?

thanks in advance…