I've noticed this a number of times and it really frustrates me since Flash is a vector drawing tool, after all. But I notice if I draw anything with Flash's vector drawing tool from the pen to a round circle, I notice jaggy artifacts in the final render. Take a look at this page with the large orange curved line:

http://www.datatv.com/lce/

See the problem? Is there some kind of setting I can use to eliminate this? Or just a Fact of Life?