Why does my iMac freeze/crash?

I have a late 2009 27-inch imac. Can anyoneplease tell me why it crashed? I got this message after it froze and crashed, by the way i played league of legends:

Interval Since Last Panic Report: 305778 sec

Panics Since Last Report: 1

Anonymous UUID: 334690FA-8770-20AC-F651-6FE65E9E76D6

Mon Sep 2 15:54:06 2013

panic(cpu 3 caller 0xffffff800ce9e53b): "TLB invalidation IPI timeout: " "CPU(s) failed to respond to interrupts, unresponsive CPU bitmap: 0x4, NMIPI acks: orig: 0x0, now: 0x0"@/SourceCache/xnu/xnu-2050.24.15/osfmk/x86_64/pmap.c:2337

Backtrace (CPU 3), Frame : Return Address

0xffffff816c71baa0 : 0xffffff800ce1d626

0xffffff816c71bb10 : 0xffffff800ce9e53b

0xffffff816c71bb90 : 0xffffff800cea2d50

0xffffff816c71bc50 : 0xffffff800cea3585

0xffffff816c71bca0 : 0xffffff800ce6720c

0xffffff816c71bd90 : 0xffffff800ce6b0e0

0xffffff816c71bdc0 : 0xffffff800ce65bdf

0xffffff816c71bdf0 : 0xffffff800d202243

0xffffff816c71be10 : 0xffffff800d264c0c

0xffffff816c71be50 : 0xffffff800ce943a3

0xffffff816c71be80 : 0xffffff800ce20b3d

0xffffff816c71beb0 : 0xffffff800ce10448

0xffffff816c71bf00 : 0xffffff800ce1961b

0xffffff816c71bf70 : 0xffffff800cea6536

0xffffff816c71bfb0 : 0xffffff800cece9e3

BSD process name corresponding to current thread: powerd

Mac OS version:

12E55

Kernel version:

Darwin Kernel Version 12.4.0: Wed May 1 17:57:12 PDT 2013; root:xnu-2050.24.15~1/RELEASE_X86_64

Kernel UUID: 896CB1E3-AB79-3DF1-B595-549DFFDF3D36

Kernel slide: 0x000000000cc00000

Kernel text base: 0xffffff800ce00000

System model name: iMac11,1 (Mac-F2268DAE)

System uptime in nanoseconds: 22083939241493

last loaded kext at 254343293362: com.apple.filesystems.msdosfs 1.8.1 (addr 0xffffff7f8d675000, size 65536)

last unloaded kext at 16137879067: com.parallels.kext.prl_usb_connect 7.0 15107.796624 (addr 0xffffff7f8d667000, size 28672)

loaded kexts:

org.virtualbox.kext.VBoxNetAdp 4.2.16

org.virtualbox.kext.VBoxNetFlt 4.2.16

org.virtualbox.kext.VBoxUSB 4.2.16

org.virtualbox.kext.VBoxDrv 4.2.16

com.parallels.kext.prl_vnic 7.0 15107.796624

com.parallels.kext.prl_netbridge 7.0 15107.796624

com.parallels.kext.prl_hid_hook 7.0 15107.796624

com.parallels.kext.prl_hypervisor 7.0 15107.796624

com.parallels.kext.prl_usb_connect 7.0 15107.796624

com.paceap.kext.pacesupport.snowleopard 5.7.2

com.usboverdrive.driver.hid 3.0.2

jp.plentycom.driver.SteerMouse 4.1.6

com.apple.filesystems.msdosfs 1.8.1

com.apple.driver.AudioAUUC 1.60

com.apple.driver.AGPM 100.12.87

com.apple.driver.AppleTyMCEDriver 1.0.2d2

com.apple.filesystems.autofs 3.0

com.apple.iokit.IOBluetoothSerialManager 4.1.4f2

com.apple.driver.AppleMikeyHIDDriver 122

com.apple.driver.AppleHDAHardwareConfigDriver 2.3.7fc4

com.apple.driver.AppleHDA 2.3.7fc4

com.apple.driver.AppleHWSensor 1.9.5d0

com.apple.driver.AppleMikeyDriver 2.3.7fc4

com.apple.driver.ACPI_SMC_PlatformPlugin 1.0.0

com.apple.driver.AppleMuxControl 3.4.5

com.apple.driver.AppleLPC 1.6.0

com.apple.driver.AppleBacklight 170.2.5

com.apple.iokit.IOBluetoothUSBDFU 4.1.4f2

com.apple.iokit.BroadcomBluetoothHCIControllerUSBTransport 4.1.4f2

com.apple.driver.AppleUpstreamUserClient 3.5.10

com.apple.driver.AppleMCCSControl 1.1.11

com.apple.kext.AMDFramebuffer 8.1.2

com.apple.ATIRadeonX2000 8.1.2

com.apple.iokit.IOUserEthernet 1.0.0d1

com.apple.Dont_Steal_Mac_OS_X 7.0.0

com.apple.driver.ApplePolicyControl 3.4.5

com.apple.driver.AppleIRController 320.15

com.apple.driver.AppleUSBCardReader 3.1.7

com.apple.driver.AppleFileSystemDriver 3.0.1

com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1

com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1

com.apple.BootCache 34

com.apple.iokit.SCSITaskUserClient 3.5.5

com.apple.driver.XsanFilter 404

com.apple.iokit.IOAHCIBlockStorage 2.3.1

com.apple.driver.AppleUSBHub 5.5.5

com.apple.iokit.AppleBCM5701Ethernet 3.6.1b4

com.apple.driver.AppleFWOHCI 4.9.6

com.apple.driver.AirPort.Atheros40 600.72.2

com.apple.driver.AppleUSBEHCI 5.5.0

com.apple.driver.AppleAHCIPort 2.5.2

com.apple.driver.AppleUSBUHCI 5.2.5

com.apple.driver.AppleEFINVRAM 1.7

com.apple.driver.AppleRTC 1.5

com.apple.driver.AppleACPIButtons 1.7

com.apple.driver.AppleHPET 1.8

com.apple.driver.AppleSMBIOS 1.9

com.apple.driver.AppleACPIEC 1.7

com.apple.driver.AppleAPIC 1.6

com.apple.driver.AppleIntelCPUPowerManagementClient 196.0.0

com.apple.nke.applicationfirewall 4.0.39

com.apple.security.quarantine 2.1

com.apple.driver.AppleIntelCPUPowerManagement 196.0.0

com.apple.driver.AppleBluetoothHIDKeyboard 170.2

com.apple.driver.AppleHIDKeyboard 170.2

com.apple.kext.triggers 1.0

com.apple.iokit.IOSerialFamily 10.0.6

com.apple.driver.DspFuncLib 2.3.7fc4

com.apple.iokit.IOAudioFamily 1.8.9fc11

com.apple.kext.OSvKernDSPLib 1.6

com.apple.iokit.IOFireWireIP 2.2.5

com.apple.driver.IOPlatformPluginLegacy 1.0.0

com.apple.driver.AppleSMBusPCI 1.0.11d0

com.apple.driver.AppleHDAController 2.3.7fc4

com.apple.iokit.IOHDAFamily 2.3.7fc4

com.apple.driver.IOPlatformPluginFamily 5.3.0d51

com.apple.driver.AppleBacklightExpert 1.0.4

com.apple.iokit.AppleBluetoothHCIControllerUSBTransport 4.1.4f2

com.apple.driver.AppleSMBusController 1.0.11d0

com.apple.kext.AMD4800Controller 8.1.2

com.apple.kext.AMDSupport 8.1.2

com.apple.iokit.IOSurface 86.0.4

com.apple.driver.AppleSMC 3.1.4d2

com.apple.driver.AppleGraphicsControl 3.4.5

com.apple.iokit.IONDRVSupport 2.3.7

com.apple.iokit.IOGraphicsFamily 2.3.7

com.apple.driver.IOBluetoothHIDDriver 4.1.4f2

com.apple.iokit.IOBluetoothFamily 4.1.4f2

com.apple.iokit.IOUSBHIDDriver 5.2.5

com.apple.iokit.IOSCSIBlockCommandsDevice 3.5.5

com.apple.iokit.IOUSBMassStorageClass 3.5.1

com.apple.driver.AppleUSBMergeNub 5.5.5

com.apple.driver.AppleUSBComposite 5.2.5

com.apple.iokit.IOSCSIMultimediaCommandsDevice 3.5.5

com.apple.iokit.IOBDStorageFamily 1.7

com.apple.iokit.IODVDStorageFamily 1.7.1

com.apple.iokit.IOCDStorageFamily 1.7.1

com.apple.iokit.IOAHCISerialATAPI 2.5.1

com.apple.iokit.IOSCSIArchitectureModelFamily 3.5.5

com.apple.iokit.IOUSBUserClient 5.5.5

com.apple.iokit.IOEthernetAVBController 1.0.2b1

com.apple.iokit.IOFireWireFamily 4.5.5

com.apple.iokit.IO80211Family 530.4

com.apple.iokit.IONetworkingFamily 3.0

com.apple.iokit.IOAHCIFamily 2.3.1

com.apple.iokit.IOUSBFamily 5.6.0

com.apple.driver.AppleEFIRuntime 1.7

com.apple.iokit.IOHIDFamily 1.8.1

com.apple.iokit.IOSMBusFamily 1.1

com.apple.security.sandbox 220.3

com.apple.kext.AppleMatch 1.0.0d1

com.apple.security.TMSafetyNet 7

com.apple.driver.DiskImages 345

com.apple.iokit.IOStorageFamily 1.8

com.apple.driver.AppleKeyStore 28.21

com.apple.driver.AppleACPIPlatform 1.7

com.apple.iokit.IOPCIFamily 2.7.3

com.apple.iokit.IOACPIFamily 1.4

com.apple.kec.corecrypto 1.0

Model: iMac11,1, BootROM IM111.0034.B02, 4 processors, Intel Core i5, 2.66 GHz, 12 GB, SMC 1.54f36

Graphics: ATI Radeon HD 4850, ATI Radeon HD 4850, PCIe, 512 MB

Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1067 MHz, 0x0198, 0x393955353432382D3034362E4130304C4620

Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1067 MHz, 0x0198, 0x393955353432382D3034362E4130304C4620

Memory Module: BANK 0/DIMM1, 2 GB, DDR3, 1067 MHz, 0x80CE, 0x4D34373142353637334548312D4346382020

Memory Module: BANK 1/DIMM1, 2 GB, DDR3, 1067 MHz, 0x80CE, 0x4D34373142353637334548312D4346382020

AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x8F), Atheros 9280: 4.0.72.0-P2P

Bluetooth: Version 4.1.4f2 12041, 2 service, 18 devices, 1 incoming serial ports

Network Service: Ethernet, Ethernet, en0

Network Service: AirPort, AirPort, en1

Serial ATA Device: ST2000DM001-1CH164, 2 TB

Serial ATA Device: OPTIARC DVD RW AD-5680H

USB Device: hub_device, 0x0424 (SMSC), 0x2514, 0xfa100000 / 2

USB Device: USB Laser Game Mouse, 0x04d9 (Holtek Semiconductor, Inc.), 0xfa50, 0xfa140000 / 5

USB Device: Internal Memory Card Reader, apple_vendor_id, 0x8403, 0xfa120000 / 4

USB Device: BRCM2046 Hub, 0x0a5c (Broadcom Corp.), 0x4500, 0xfa110000 / 3

USB Device: Bluetooth USB Host Controller, apple_vendor_id, 0x8215, 0xfa111000 / 8

USB Device: hub_device, 0x0424 (SMSC), 0x2514, 0xfd100000 / 2

USB Device: Built-in iSight, apple_vendor_id, 0x8502, 0xfd110000 / 4

USB Device: IR Receiver, apple_vendor_id, 0x8242, 0xfd120000 / 3