My X server consistently crashes. It seems like this is happening when the X server is idle. This behaviour is new with 12.04. This is only happening on the second display of a multiseat system. Is there a configuration change I can make to stop this?

X.Org X Server 1.11.3
Release Date: 2011-12-16
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.42-26-generic x86_64 Ubuntu
Current Operating System: Linux Desktop 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64
Kernel command line: BOOT_IMAGE=/vmlinuz-3.2.0-29-generic root=/dev/mapper/Group1-Root ro ramdisk_size=512000 quiet splash vt.handoff=7
Build Date: 04 August 2012  01:51:23AM
xorg-server 2:1.11.4-0ubuntu10.7 (For technical support please see http://www.ubuntu.com/support) 
Current version of pixman: 0.24.4
    Before reporting problems, check http://wiki.x.org
    to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
    (++) from command line, (!!) notice, (II) informational,
    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.1.log", Time: Sun Sep  2 22:37:06 2012
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"

Backtrace:
0: /usr/bin/X (xorg_backtrace+0x26) [0x7fcee86be846]
1: /usr/bin/X (0x7fcee8536000+0x18c6ea) [0x7fcee86c26ea]
2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fcee785c000+0xfcb0) [0x7fcee786bcb0]
3: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so (0x7fcee14ba000+0x902a9) [0x7fcee154a2a9]
4: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so (0x7fcee14ba000+0xfd5e7) [0x7fcee15b75e7]
5: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so (0x7fcee14ba000+0x4d6b92) [0x7fcee1990b92]
6: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so (0x7fcee14ba000+0x4d74d5) [0x7fcee19914d5]
7: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/nvidia_drv.so (0x7fcee14ba000+0x4d767d) [0x7fcee199167d]
8: /usr/bin/X (0x7fcee8536000+0x1196ec) [0x7fcee864f6ec]
9: /usr/bin/X (0x7fcee8536000+0xe8ad5) [0x7fcee861ead5]
10: /usr/bin/X (0x7fcee8536000+0xe9d45) [0x7fcee861fd45]

/etc/X11/xorg.conf

Section "ServerLayout"
    Identifier     "Desktop"
    Screen      0  "DesktopScreen" 0 0
    InputDevice    "DesktopMouse"          "CorePointer"
    InputDevice    "DesktopKeyboard"       "CoreKeyboard"
    Option         "AutoAddDevices"        "false"
    Option         "AllowEmptyInput"       "true"
    Option         "AutoEnableDevices"     "false"
EndSection

Section "ServerLayout"
    Identifier     "Desktop2"
    Screen      1  "Desktop2Screen" 0 0
    InputDevice    "Desktop2Mouse"          "CorePointer"
    InputDevice    "Desktop2Keyboard"       "CoreKeyboard"
    Option         "AutoAddDevices"        "false"
    Option         "AllowEmptyInput"       "true"
    Option         "AutoEnableDevices"     "false"
EndSection

Section "Module"
    Load           "dbe"
    Load           "extmod"
    Load           "type1"
    Load           "freetype"
    Load           "glx"
EndSection

Section "Files"
EndSection

Section "ServerFlags"
    Option "AutoAddDevices"     "false"
    Option "AutoEnableDevices"  "false"
    Option "AllowMouseOpenFail" "on"
    Option "AllowEmptyInput"    "on"
    Option "ZapWarning"         "on"
    Option "HandleSepcialKeys"  "off" # Zapping on
    Option "DRI2"               "on"
    Option "Xinerama"           "0"
EndSection

# Desktop Mouse
Section "InputDevice"
    Identifier     "DesktopMouse"
    Driver         "evdev"
    Option         "Device"          "/dev/input/event3"
    Option         "Protocol"        "auto"
    Option         "GrabDevice"      "on"
    Option         "Emulate3Buttons" "no"
    Option         "Buttons"         "5"
    Option         "ZAxisMapping"    "4 5"
    Option         "SendCoreEvents"  "true"
EndSection

# Desktop2 Mouse
Section "InputDevice"
    Identifier     "Desktop2Mouse"
    Driver         "evdev"
    Option         "Device"          "/dev/input/event5"
    Option         "Protocol"        "auto"
    Option         "GrabDevice"      "on"
    Option         "Emulate3Buttons" "no"
    Option         "Buttons"         "5"
    Option         "ZAxisMapping"    "4 5"
    Option         "SendCoreEvents"  "true"
EndSection

Section "InputDevice"
    Identifier     "DesktopKeyboard"
    Driver         "evdev"
    Option         "Device"    "/dev/input/event4"
    Option         "XkbRules"  "xorg"
    Option         "XkbModel"  "105"
    Option         "XkbLayout" "us"
    Option         "Protocol"  "Standard"
    Option         "GrabDevice" "on"
EndSection

Section "InputDevice"
    Identifier     "Desktop2Keyboard"
    Driver         "evdev"
    Option         "Device"    "/dev/input/event6"
    Option         "XkbRules"  "xorg"
    Option         "XkbModel"  "105"
    Option         "XkbLayout" "us"
    Option         "Protocol"  "Standard"
    Option         "GrabDevice" "on"
EndSection

Section "Monitor"
    Identifier     "Desktop2Monitor"
    VendorName     "Acer"
    ModelName      "Acer G235H"
    HorizSync       30.0 - 83.0
    VertRefresh     56.0 - 75.0
    Option         "DPMS"
EndSection

Section "Monitor"
    Identifier     "DesktopMonitor"
    VendorName     "Acer"
    ModelName      "Acer H213H"
    HorizSync       30.0 - 83.0
    VertRefresh     56.0 - 75.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "EVGACard"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 560 Ti"
    Option         "Coolbits" "1"
    BusID          "PCI:2:0:0"
    Screen          0
EndSection

Section "Device"
    Identifier     "XFXCard"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 9800"
    Option         "Coolbits" "1"
    BusID          "PCI:5:0:0"
    Screen          0
EndSection

Section "Screen"
    Identifier     "DesktopScreen"
    Device         "EVGACard"
    Monitor        "DesktopMonitor"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Desktop2Screen"
    Device         "XFXCard"
    Monitor        "Desktop2Monitor"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection