Mutter crashes after lock screen

[Matt Pharoah]

Problem Description:
After locking the screen, mutter will consistently (always repeatable) crash, forcing me to restart it using only the mouse.

Steps to Reproduce:
1) Lock the screen
That's it

Error Output:
Running mutter --replace in the terminal, then locking the screen and unlocking it again gives the following output:
Window manager warning: Log level 16: The program 'mutter' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 3776 error_code 3 request_code 155 minor_code 1)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

Additional Information:
I am using GNOME Classic (gnome-fallback) with mutter on Ubuntu 11.10 64-bit on a System76 Gazelle computer. My graphics card is a GeForce GTX 560M.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: mutter 3.2.1-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-13.22-generic 3.0.6
Uname: Linux 3.0.0-13-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Sat Dec 3 14:51:06 2011
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
SourcePackage: mutter
UpgradeStatus: No upgrade log present (probably fresh install)

[dino99 (9d9)]

Oneiric is no more maintained since a while