Forwarding this bug from Ubuntu reporter tr33m4n:
http://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/747962

[Problem]
Yet another i945, probable dupe.  PGTBL_ER: 0x00000102 this time, which is a bit different.

[Original Description]
Running Ubuntu 11.04 32bit on an intel MacBook 1.1. This error is present all the time whilst using the system

Description:	Ubuntu Natty (development branch)
Release:	11.04
xserver-xorg-video-intel:
  Installed: 2:2.14.0-4ubuntu6
  Candidate: 2:2.14.0-4ubuntu6
  Version table:
 *** 2:2.14.0-4ubuntu6 0
        500 http://gb.archive.ubuntu.com/ubuntu/ natty/main i386 Packages
        100 /var/lib/dpkg/status

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: xserver-xorg-video-intel 2:2.14.0-4ubuntu6
ProcVersionSignature: Ubuntu 2.6.38-8.40~ppa1-lowlatency 2.6.38
Uname: Linux 2.6.38-8-lowlatency i686
Architecture: i386
Chipset: i945gm
CurrentDmesg:
 
Date: Mon Mar 28 20:52:31 2011
DistroCodename: natty
DistroVariant: ubuntu
DuplicateSignature: (ESR: 0x00000010 PGTBL_ER: 0x00000102)
ExecutablePath: /usr/share/apport/apport-gpu-error-intel.py
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110302)
InterpreterPath: /usr/bin/python2.7
MachineType: Apple Computer, Inc. MacBook1,1
ProcCmdline: /usr/bin/python /usr/share/apport/apport-gpu-error-intel.py
ProcEnviron:
 
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-7-lowlatency root=UUID=91a22f9a-bb2a-428c-bf47-e83b1414ec08 ro crashkernel=384M-2G:64M,2G-:128M quiet splash ipv6.disable=1 vt.handoff=7
RelatedPackageVersions:
 xserver-xorg             1:7.6~3ubuntu11
 libdrm2                  2.4.23-1ubuntu5
 xserver-xorg-video-intel 2:2.14.0-4ubuntu4
SourcePackage: xserver-xorg-video-intel
Title: [i945gm] GPU lockup (ESR: 0x00000010 PGTBL_ER: 0x00000102)
UdevDb: Error: [Errno 2] No such file or directory
UpgradeStatus: Upgraded to natty on 2011-03-25 (7 days ago)
UserGroups:
 
dmi.bios.date: 10/12/06
dmi.bios.vendor: Apple Computer, Inc.
dmi.bios.version: MB11.88Z.0061.B03.0610121324
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Mac-F4208CC8
dmi.board.vendor: Apple Computer, Inc.
dmi.board.version: PVT
dmi.chassis.asset.tag: Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Computer, Inc.
dmi.chassis.version: Mac-F4208CC8
dmi.modalias: dmi:bvnAppleComputer,Inc.:bvrMB11.88Z.0061.B03.0610121324:bd10/12/06:svnAppleComputer,Inc.:pnMacBook1,1:pvr1.0:rvnAppleComputer,Inc.:rnMac-F4208CC8:rvrPVT:cvnAppleComputer,Inc.:ct10:cvrMac-F4208CC8:
dmi.product.name: MacBook1,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Computer, Inc.
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.1-0ubuntu3
version.xserver-xorg: xserver-xorg 1:7.6+4ubuntu1