While running gnome-shell from the command line, the following warnings are shown:

...
     JS G NS: Found info type OBJECT for 'GtkEmbed' in namespace 'Shell'
   JS G REPO: Initializing dynamic class GtkEmbed 0x2ce7d10
    JS G OBJ: Defined class GtkEmbed prototype 0x2d6ec80 class 0x2ce7d10 in object 0x272ba80
    JS G PRM: Wrapping GParamObject 'focus-window' on MetaDisplay with JSObject
    JS G PRM: JSObject created with param instance 0x26b4850 type GParamObject
    JS G OBJ: Defining method get_window_app in prototype for ShellAppMonitor (Shell.AppMonitor)
WARNING: Application calling GLX 1.3 function "glXCreatePixmap" when GLX 1.3 is not supported! This is an application bug!
WARNING: Application calling GLX 1.3 function "glXDestroyPixmap" when GLX 1.3 is not supported! This is an application bug!

System info:

Karmic beta 2.6.31-13-generic
gnome-shell 2.27.3-0ubuntu1
ATI Mobility X1600 (using standard drivers shipped with Ubuntu).

Although no outwardly apparent issues resulted, I thought I'd report it none-the-less since the warning messages named themselves as bugs :)

ProblemType: Bug
Architecture: amd64
Date: Mon Oct 12 07:35:10 2009
DistroRelease: Ubuntu 9.10
Package: gnome-shell 2.27.3-0ubuntu1
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-13.44-generic
SourcePackage: gnome-shell
Uname: Linux 2.6.31-13-generic x86_64

(Originally reported downstream in Ubuntu bug-tracking...See: https://bugs.edge.launchpad.net/ubuntu/+source/gnome-shell/+bug/449467)