I've set the Background Color of a simple flash intro to #333333. The HTML page it navigates to upon finishing the animation has a background color of #333333.
The Flash BG renders lighter once it's displayed in a browser. It's fine in Flash, fine in a flash-player after being exported, but lighter once played back from the web. This feels like a Color Profile issue I had with Photoshop a few months ago, the culprit of which i found to be my monitor settings.