we've had that issue before, in the end we got it right by just tweaking the settings a bit and exporting again... pain in the butt... but hey, if it works... :) be sure to convert using CS Media Encoder.
Sent from my HTC
General notice: from now on, I would like to ask everyone to put [AS2] or [AS3] (corresponding to the version of actionscript you are using on your project) in front of their post titles when the question is actionscript related! Please help us help you faster. Thank you.