Xorg crashed with SIGABRT in raise()

error apport dialog appeared sometime after initial login having applied ppa:unity-team/sru. no apparent symptoms of failure, everything actually seems fine. (not sure error report isn't of an error that occurred before this session.)

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: xserver-xorg-core 2:1.13.0-0ubuntu6
ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7
Uname: Linux 3.5.0-18-generic x86_64
NonfreeKernelModules: nvidia
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 304.43 Sun Aug 19 20:14:03 PDT 2012
 GCC version: gcc version 4.7.2 (Ubuntu/Linaro 4.7.2-2ubuntu1)
.tmp.unity.support.test.0:

ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
Date: Mon Nov 26 20:58:13 2012
DistUpgraded: 2012-10-02 18:10:52,877 DEBUG enabling apt cron job
DistroCodename: quantal
DistroVariant: ubuntu
DkmsStatus:
 nvidia-current, 304.43, 3.5.0-17-generic, x86_64: installed
 nvidia-current, 304.43, 3.5.0-18-generic, x86_64: installed
ExecutablePath: /usr/bin/Xorg
GraphicsCard:
 NVIDIA Corporation GF108 [GeForce GT 520] [10de:0de4] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Device [1043:83d2]
InstallationDate: Installed on 2012-07-20 (132 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
JockeyStatus:
 kmod:nvidia_experimental_304 - Experimental NVIDIA binary Xorg driver, kernel module and VDPAU library (Proprietary, Disabled, Not in use)
 kmod:nvidia_experimental_310 - Experimental NVIDIA binary Xorg driver, kernel module and VDPAU library (Proprietary, Disabled, Not in use)
 kmod:nvidia_current - nvidia_current (Proprietary, Enabled, Not in use)
 kmod:nvidia_current_updates - NVIDIA binary Xorg driver, kernel module and VDPAU library (Proprietary, Disabled, Not in use)
MachineType: System manufacturer System Product Name
MarkForUpload: True
ProcCmdline: /usr/bin/X :1 -core -auth /var/run/lightdm/root/:1 -nolisten tcp vt7 -novtswitch
ProcEnviron:

ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-18-generic root=UUID=afbd2fa0-562f-40c4-a5a4-f4f0cf2d4ba8 ro quiet splash
Signal: 6
SourcePackage: nvidia-graphics-drivers
StacktraceTop:
 raise () from /lib/x86_64-linux-gnu/libc.so.6
 abort () from /lib/x86_64-linux-gnu/libc.so.6
 OsAbort ()
 ?? ()
 FatalError ()
Title: Xorg crashed with SIGABRT in raise()
UpgradeStatus: Upgraded to quantal on 2012-10-02 (57 days ago)
UserGroups:

dmi.bios.date: 05/25/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0303
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: P6X58D-E
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0303:bd05/25/2010:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP6X58D-E:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
version.compiz: compiz 1:0.9.8.6-0ubuntu1~test1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.39-0ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.0-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.0-0ubuntu1
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.13.0-0ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.99.99~git20120913.8637f772-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.20.9-0ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.2-0ubuntu3