This problem is often reported when using components or the attachMovie method. This can interfere with preloaders and requires all of the component or attached clip to download in the first frame of the movie completely, before the preload code can fire. Here are a couple links that probably explain it better than I can.......and how to fix it.........
And...... this forum is small enough that there is no need to cross post the same question to multiple forums.
Hope it helps
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- Oliver Wendell Holmes