Comment 27 for bug 157319

I'm also affected, not so much the issue of annoying error messages each time an X app is launched but rather that some apps just don't start, e.g.
$ gnome-system-monitor
Xlib: extension "RANDR" missing on display ":0.0".

I need Xinerama because of dual head display with one screen rotated

I'm using Lucid
Linux mendel 2.6.32-37-generic #81-Ubuntu SMP Fri Dec 2 20:32:42 UTC 2011 x86_64 GNU/Linux
HW NVIDIA Corporation Quadro FX 580
SW NVIDIA prop driver version current