10.0.1 is very old, we're on 11.2 now. Do you know about when this started breaking for you? I'd suggest two things. First, you might want to post over on the Flash Pro forums as there's a larger developer audience there and someone might have a quick answer for you. Next, you might want to open a new bug at bugbase.adobe.com. Please include detailed steps to reproduce, along with a link to your site and / or sample code so we can test this internally.