Version: (using KDE 4.0.0) Installed from: Gentoo Packages OS: Linux In KDE 4.0.1 I never managed to view any flash content at all. On youtube, nspluginviewer takes 100% CPU time constantly, and never gets to the point of playing anything. Other websites failed in the same way.
I just tried a youtube video and it played fine ( http://www.youtube.com/watch?v=eBGIQ7ZuuiU ). I'm using trunk rev. 818792. Does it still happen with you in recent versions like 4.0.5 or 4.1 beta?
Please reopen the bug if the bug is still present.