Flash 8 transparent window oddities

I usually don’t use transparent flash files but something came up where I need to use it for a website that is appx 1024 pixels tall. Now it works fine up until the point where I run it on smaller monitors where scrolling is needed. Once I start scrolling, objects (graphic and movieclip symbols) change appearance; transparent symbols become more opaque and strange artifacts appear around the edges of PNG files with transparency where they blur and fade out. If I resize the browser window it jumps back to how it is supposed to look.

Any ideas of what is causing this or is this a bug in flash? I believe I am running the latest flash player 9.

Thanks