This may or may not be relevant, but I recently downgraded from Flash 9 to the latest version of Flash 8, after having some problems with Beatport (
www.beatport.com -- an online music store that is entirely Flash-based). Frustratingly, I have different problems with the same site when using Flash 8, but they are less of a problem than the ones I encountered with the Flash 9 plugin (which made several key features fairly problematic).
Don't know whether there's anything wrong with Flash 9 itself, or if something was simply changed in Flash 9 that created some incompatibilities with Flash content designed for earlier versions, but either way, juust wanted to suggest that it might not have anything to do with OmniWeb. Definitely test the sites with other browsers to isolate whether it's the plugin or the browser.