OSX Panic about once a week

I am running OSX 10.6.6 and I this is the second kernel panic in 2 weeks.

Here is the log that gets sent to Apple. Help!

 Model Name:    MacBook Pro
  Model Identifier: MacBookPro6,2
  Processor Name:   Intel Core i7
  Processor Speed:  2.66 GHz
  Number Of Processors: 1
  Total Number Of Cores:    2
  L2 Cache (per core):  256 KB
  L3 Cache: 4 MB
  Memory:   8 GB
  Processor Interconnect Speed: 4.8 GT/s
  Boot ROM Version: MBP61.0057.B0C
  SMC Version (system): 1.58f16
  Serial Number (system):   W80208GLAGZ
  Hardware UUID:    
  Sudden Motion Sensor:
  State:    Enabled

Interval Since Last Panic Report:  320570 sec
Panics Since Last Report:          1
Anonymous UUID:                   

Sun Jan 23 11:28:22 2011
panic(cpu 0 caller 0x226b53): "thread_invoke: preemption_level -1, possible cause: unlocking an unlocked mutex or spinlock"@/SourceCache/xnu/xnu-1504.9.26/osfmk/kern/sched_prim.c:1471
Backtrace (CPU 0), Frame : Return Address (4 potential args on stack)
0x7c373998 : 0x21b50c (0x5d4438 0x7c3739cc 0x223974 0x0) 
0x7c3739e8 : 0x226b53 (0x58babc 0xffffffff 0x58ba54 0x226423) 
0x7c373a68 : 0x227259 (0xdab93f0 0x0 0x7c373b58 0xffffffff) 
0x7c373ad8 : 0x2272e7 (0x0 0x0 0x0 0xdab93d4) 
0x7c373af8 : 0x211b5f (0x0 0x0 0xffffffff 0x0) 
0x7c373b28 : 0x21dfac (0xdab4514 0x0 0xffffffff 0x0) 
0x7c373b88 : 0x21e0a7 (0x7c373bc4 0x5c 0x2c 0x0) 
0x7c373ba8 : 0x23d517 (0x7c373bc4 0x5c 0x2c 0x10) 
0x7c373c38 : 0x21b7f8 (0xd48cd90 0xdab4570 0xda45af0 0x1) 
0x7c373ee8 : 0x21bb2a (0xdab93d4 0x1 0x7c373fa0 0x2) 
0x7c373f38 : 0x2aa4e2 (0x1 0x7c373fa0 0x2 0x1) 
0x7c373fc8 : 0x2a080a (0xd2db824 0x0 0x10 0x0) 

BSD process name corresponding to current thread: configd

Mac OS version:
10J567

Kernel version:
Darwin Kernel Version 10.6.0: Wed Nov 10 18:13:17 PST 2010; root:xnu-1504.9.26~3/RELEASE_I386
System model name: MacBookPro6,2 (Mac-F22586C8)

System uptime in nanoseconds: 89117851176904
unloaded kexts:
com.apple.filesystems.msdosfs   1.6.3 (addr 0xb9347000, size 0x53248) - last unloaded 85871516725126
loaded kexts:
com.cisco.nke.ipsec 2.0.1
com.apple.driver.AppleBluetoothMultitouch   54 - last loaded 80306184138334
com.apple.filesystems.udf   2.1
com.apple.driver.AppleHWSensor  1.9.3d0
com.apple.filesystems.autofs    2.1.0
com.apple.driver.AppleMikeyHIDDriver    1.2.0
com.apple.driver.AppleHDA   1.9.9f12
com.apple.driver.AppleMikeyDriver   1.9.9f12
com.apple.driver.AGPM   100.12.19
com.apple.driver.AppleUpstreamUserClient    3.4.5
com.apple.driver.AppleMCCSControl   1.0.17
com.apple.driver.IOBluetoothBNEPDriver  2.3.8f7
com.apple.driver.AudioAUUC  1.13
com.apple.driver.AppleIntelHDGraphics   6.2.6
com.apple.driver.AppleIntelHDGraphicsFB 6.2.6
com.apple.driver.SMCMotionSensor    3.0.0d4
com.apple.kext.AppleSMCLMU  1.5.0d3
com.apple.Dont_Steal_Mac_OS_X   7.0.0
com.apple.iokit.CHUDUtils   364
com.apple.iokit.CHUDProf    366
com.apple.driver.AudioIPCDriver 1.1.6
com.apple.driver.AppleIntelNehalemProfile   19
com.apple.GeForce   6.2.6
com.apple.driver.ACPI_SMC_PlatformPlugin    4.5.0d5
com.apple.driver.AppleLPC   1.4.12
com.apple.driver.AppleGraphicsControl   2.8.68
com.apple.driver.AppleUSBTCButtons  200.3.2
com.apple.driver.AppleUSBCardReader 2.5.8
com.apple.driver.AppleUSBTCKeyboard 200.3.2
com.apple.driver.AppleIRController  303.8
com.apple.BootCache 31
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1
com.apple.iokit.SCSITaskUserClient  2.6.5
com.apple.iokit.IOAHCIBlockStorage  1.6.3
com.apple.driver.AppleUSBHub    4.1.7
com.apple.driver.AppleFWOHCI    4.7.1
com.apple.iokit.AppleBCM5701Ethernet    2.3.9b6
com.apple.driver.AirPortBrcm43224   426.36.1
com.apple.driver.AppleEFINVRAM  1.4.0
com.apple.driver.AppleSmartBatteryManager   160.0.0
com.apple.driver.AppleUSBEHCI   4.1.7
com.apple.driver.AppleAHCIPort  2.1.5
com.apple.driver.AppleACPIButtons   1.3.5
com.apple.driver.AppleRTC   1.3.1
com.apple.driver.AppleHPET  1.5
com.apple.driver.AppleSMBIOS    1.6
com.apple.driver.AppleACPIEC    1.3.5
com.apple.driver.AppleAPIC  1.4
com.apple.driver.AppleIntelCPUPowerManagementClient 105.13.0
com.apple.security.sandbox  1
com.apple.security.quarantine   0
com.apple.nke.applicationfirewall   2.1.11
com.apple.driver.AppleIntelCPUPowerManagement   105.13.0
com.apple.driver.IOBluetoothHIDDriver   2.3.8f7
com.apple.driver.AppleMultitouchDriver  207.10
com.apple.driver.DspFuncLib 1.9.9f12
com.apple.driver.AppleProfileReadCounterAction  25
com.apple.iokit.IOFireWireIP    2.0.3
com.apple.driver.AppleSMBusController   1.0.8d0
com.apple.nvidia.nv50hal    6.2.6
com.apple.driver.AppleProfileTimestampAction    18
com.apple.driver.AppleProfileThreadInfoAction   23
com.apple.driver.AppleProfileRegisterStateAction    19
com.apple.driver.AppleProfileKEventAction   18
com.apple.driver.AppleProfileCallstackAction    34
com.apple.iokit.IOSurface   74.2
com.apple.iokit.IOBluetoothSerialManager    2.3.8f7
com.apple.iokit.IOSerialFamily  10.0.3
com.apple.iokit.CHUDKernLib 365
com.apple.iokit.IOAudioFamily   1.8.0fc1
com.apple.kext.OSvKernDSPLib    1.3
com.apple.driver.AppleHDAController 1.9.9f12
com.apple.iokit.IOHDAFamily 1.9.9f12
com.apple.NVDAResman    6.2.6
com.apple.iokit.AppleProfileFamily  56
com.apple.driver.AppleSMC   3.1.0d3
com.apple.driver.IOPlatformPluginFamily 4.5.0d5
com.apple.driver.AppleSMBusPCI  1.0.8d0
com.apple.iokit.IONDRVSupport   2.2
com.apple.iokit.IOGraphicsFamily    2.2
com.apple.driver.BroadcomUSBBluetoothHCIController  2.3.8f7
com.apple.driver.AppleUSBBluetoothHCIController 2.3.8f7
com.apple.iokit.IOBluetoothFamily   2.3.8f7
com.apple.iokit.IOSCSIBlockCommandsDevice   2.6.5
com.apple.iokit.IOUSBMassStorageClass   2.6.5
com.apple.driver.AppleUSBMultitouch 206.6
com.apple.iokit.IOUSBHIDDriver  4.1.5
com.apple.driver.AppleUSBMergeNub   4.1.5
com.apple.driver.AppleUSBComposite  3.9.0
com.apple.iokit.IOSCSIMultimediaCommandsDevice  2.6.5
com.apple.iokit.IOBDStorageFamily   1.6
com.apple.iokit.IODVDStorageFamily  1.6
com.apple.iokit.IOCDStorageFamily   1.6
com.apple.driver.XsanFilter 402.1
com.apple.iokit.IOAHCISerialATAPI   1.2.5
com.apple.iokit.IOSCSIArchitectureModelFamily   2.6.5
com.apple.iokit.IOUSBUserClient 4.1.5
com.apple.iokit.IOFireWireFamily    4.2.6
com.apple.iokit.IO80211Family   312
com.apple.iokit.IONetworkingFamily  1.9
com.apple.iokit.IOUSBFamily 4.1.7
com.apple.iokit.IOAHCIFamily    2.0.4
com.apple.driver.AppleEFIRuntime    1.4.0
com.apple.iokit.IOHIDFamily 1.6.5
com.apple.iokit.IOSMBusFamily   1.1
com.apple.kext.AppleMatch   1.0.0d1
com.apple.security.TMSafetyNet  6
com.apple.driver.DiskImages 289
com.apple.iokit.IOStorageFamily 1.6.2
com.apple.driver.AppleACPIPlatform  1.3.5
com.apple.iokit.IOPCIFamily 2.6
com.apple.iokit.IOACPIFamily    1.3.0
Model: MacBookPro6,2, BootROM MBP61.0057.B0C, 2 processors, Intel Core i7, 2.66 GHz, 8 GB, SMC 1.58f16
Graphics: NVIDIA GeForce GT 330M, NVIDIA GeForce GT 330M, PCIe, 512 MB
Graphics: Intel HD Graphics, Intel HD Graphics, Built-In, 288 MB
Memory Module: global_name
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x93), Broadcom BCM43xx 1.0 (5.10.131.36.1)
Bluetooth: Version 2.3.8f7, 2 service, 19 devices, 1 incoming serial ports
Network Service: AirPort, AirPort, en1
Serial ATA Device: ST9500420ASG, 465.76 GB
Serial ATA Device: MATSHITADVD-R   UJ-898
USB Device: Hub, 0x0424  (SMSC), 0x2514, 0xfd100000
USB Device: Built-in iSight, 0x05ac  (Apple Inc.), 0x8507, 0xfd110000
USB Device: IR Receiver, 0x05ac  (Apple Inc.), 0x8242, 0xfd120000
USB Device: Hub, 0x0424  (SMSC), 0x2514, 0xfa100000
USB Device: Internal Memory Card Reader, 0x05ac  (Apple Inc.), 0x8403, 0xfa130000
USB Device: BRCM2070 Hub, 0x0a5c  (Broadcom Corp.), 0x4500, 0xfa110000
USB Device: Bluetooth USB Host Controller, 0x05ac  (Apple Inc.), 0x8218, 0xfa113000
USB Device: Apple Internal Keyboard / Trackpad, 0x05ac  (Apple Inc.), 0x0237, 0xfa120000

It seems there is a Cisco VPN kernel extension loaded. It's known for being a bit problematic, and also happens to be a relatively old version. I would contact the support staff for your VPN to see if there's a newer version of the client available (I checked Cisco's site myself, but you have to have a paid account to download) or, if you don't need it, try removing the extension.