Comment 210 for bug 192888

Jeremy,

Ensure you have the correct configuration enabled (your post suggests you do) and that libflashsupport is *not* installed, and disable compiz. Maybe I'm crazy, but I could have sworn I saw a "Known Issues" entry mentioning instability when using compiz because of XRender, but I can't seem to find it in the release notes of Flash anymore.

Also, if you're using 64bit Ubuntu, libflashsupport is actually provided in the "ia32-libs" package, I think.