Elastic menu component works in test but not in publish

I purchased an elastic menu flash component that uses AS3. Unfortunately, I’ve only just waded into AS2.

I’m trying to replace the generic colored background with an image that is masked. Unfortunately, turning the layer into a mask breaks the functionality. The weird thing is that it works fine in Test Mode (Ctrl+Enter) and if published as an EXE. It just doesn’t work as an swf.

Has anyone run into this weird inconsistency before? Also, what is the best way to get into that component and possibly modify it?