kernel error on start up macbook pro mid 2009

ive had this computer since mid 2009, and now when i start up i get a kernel error, it happened once last week and then it started normally.

im currently on safe boot

here is the error code

Interval Since Last Panic Report: 6665 sec
Panics Since Last Report: 4
Anonymous UUID: 23D0CADA-E524-41E5-A94E-3B1F5EB7F30D

Tue Apr 24 17:49:18 2012
panic(cpu 0 caller 0x483cbb): "_MALLOC: kalloc returned NULL (potential leak), size 4138922952"@/SourceCache/xnu/xnu-1504.15.3/bsd/kern/kern_malloc.c:572
Backtrace (CPU 0), Frame : Return Address (4 potential args on stack)
0x51103bd8 : 0x21b837 (0x5dd7fc 0x51103c0c 0x223ce1 0x0)
0x51103c28 : 0x483cbb (0x5d0054 0xf6b2f3c8 0x0 0xb5979e33)
0x51103c48 : 0x575e2264 (0xf6b2f3c8 0x50 0x4 0x0)
0x51103c98 : 0x575e27a0 (0x42a69004 0x0 0x0 0x0)
0x51103d68 : 0x575e3cfa (0x200 0x0 0x18 0x22eeee)
0x51103dd8 : 0x495644 (0x575e5aa0 0x0 0x0 0x51103e50)
0x51103e28 : 0x495786 (0x51103e50 0x30 0x51103e58 0x51096063)
0x51103ec8 : 0x49442f (0x739c7e0 0x51103f24 0x2 0x0)
0x51103f78 : 0x4f82fb (0x739c7e0 0x6bca8c8 0x7105c54 0x1)
0x51103fc8 : 0x2a251d (0x6bca8c4 0x0 0x10 0x6bca8c4)
Kernel Extensions in backtrace (with dependencies):
com.apple.BootCache(31.1)@0x575e1000->0x575e5fff

BSD process name corresponding to current thread: BootCacheControl

Mac OS version:
10K549

Kernel version:
Darwin Kernel Version 10.8.0: Tue Jun 7 16:33:36 PDT 2011; root:xnu-1504.15.3~1/RELEASE_I386
System model name: MacBookPro5,5 (Mac-F2268AC8)

System uptime in nanoseconds: 3308325051
unloaded kexts:
(none)
loaded kexts:
com.apple.driver.AppleUSBTCButtons 201.6 - last loaded 2081075952
com.apple.driver.AppleUSBTCKeyEventDriver 201.6
com.apple.driver.AppleUSBTCKeyboard 201.6
com.apple.driver.AppleIRController 303.8
com.apple.driver.AppleUSBCardReader 2.6.1
com.apple.iokit.SCSITaskUserClient 2.6.8
com.apple.iokit.IOAHCIBlockStorage 1.6.4
com.apple.driver.AppleFWOHCI 4.7.3
com.apple.BootCache 31.1
com.apple.AppleFSCompression.AppleFSCompressionTyp eZlib 1.0.0d1
com.apple.driver.AppleAHCIPort 2.1.7
com.apple.driver.AppleUSBHub 4.2.4
com.apple.driver.AppleEFINVRAM 1.4.0
com.apple.driver.AppleUSBEHCI 4.2.4
com.apple.driver.AppleUSBOHCI 4.2.0
com.apple.driver.AppleRTC 1.3.1
com.apple.driver.AppleHPET 1.5
com.apple.driver.AppleSmartBatteryManager 160.0.0
com.apple.driver.AppleACPIButtons 1.3.6
com.apple.driver.AppleSMBIOS 1.7
com.apple.driver.AppleACPIEC 1.3.6
com.apple.driver.AppleAPIC 1.4
com.apple.driver.AppleIntelCPUPowerManagementClien t 142.6.0
com.apple.security.sandbox 1
com.apple.security.quarantine 0
com.apple.nke.applicationfirewall 2.1.14
com.apple.driver.AppleIntelCPUPowerManagement 142.6.0
com.apple.driver.BroadcomUSBBluetoothHCIController 2.4.5f3
com.apple.driver.AppleUSBBluetoothHCIController 2.4.5f3
com.apple.iokit.IOBluetoothFamily 2.4.5f3
com.apple.driver.AppleUSBMultitouch 207.7
com.apple.iokit.IOUSBHIDDriver 4.2.0
com.apple.iokit.IOUSBMassStorageClass 2.6.7
com.apple.iokit.IOSCSIBlockCommandsDevice 2.6.8
com.apple.driver.AppleUSBMergeNub 4.2.4
com.apple.driver.AppleUSBComposite 3.9.0
com.apple.iokit.IOSCSIMultimediaCommandsDevice 2.6.8
com.apple.iokit.IOBDStorageFamily 1.6
com.apple.iokit.IODVDStorageFamily 1.6
com.apple.iokit.IOCDStorageFamily 1.6.1
com.apple.driver.XsanFilter 402.1
com.apple.iokit.IOAHCISerialATAPI 1.2.6
com.apple.iokit.IOSCSIArchitectureModelFamily 2.6.8
com.apple.iokit.IOFireWireFamily 4.2.6
com.apple.driver.AppleFileSystemDriver 2.0
com.apple.iokit.IOAHCIFamily 2.0.6
com.apple.iokit.IOUSBUserClient 4.2.4
com.apple.driver.AppleEFIRuntime 1.4.0
com.apple.iokit.IOUSBFamily 4.2.4
com.apple.iokit.IOHIDFamily 1.6.6
com.apple.iokit.IOSMBusFamily 1.1
com.apple.security.TMSafetyNet 6
com.apple.kext.AppleMatch 1.0.0d1
com.apple.driver.DiskImages 289.1
com.apple.iokit.IOStorageFamily 1.6.3
com.apple.driver.AppleACPIPlatform 1.3.6
com.apple.iokit.IOPCIFamily 2.6.5
com.apple.iokit.IOACPIFamily 1.3.0
Model: MacBookPro5,5, BootROM MBP55.00AC.B03, 2 processors, Intel Core 2 Duo, 2.26 GHz, 4 GB, SMC 1.47f2
Graphics: NVIDIA GeForce 9400M, NVIDIA GeForce 9400M, PCI, 256 MB
Memory Module: global_name
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x8D), Broadcom BCM43xx 1.0 (5.10.131.42.4)
Bluetooth: Version 2.4.5f3, 2 service, 19 devices, 0 incoming serial ports
Network Service: AirPort, AirPort, en1
Serial ATA Device: FUJITSU MJA2160BH FFS G1, 149.05 GB
Serial ATA Device: HL-DT-ST DVDRW GS23N
USB Device: Built-in iSight, 0x05ac (Apple Inc.), 0x8507, 0x24400000 / 2
USB Device: Internal Memory Card Reader, 0x05ac (Apple Inc.), 0x8403, 0x26500000 / 2
USB Device: BRCM2046 Hub, 0x0a5c (Broadcom Corp.), 0x4500, 0x06100000 / 2
USB Device: Bluetooth USB Host Controller, 0x05ac (Apple Inc.), 0x8213, 0x06110000 / 3
USB Device: Apple Internal Keyboard / Trackpad, 0x05ac (Apple Inc.), 0x0236, 0x04600000 / 3
USB Device: IR Receiver, 0x05ac (Apple Inc.), 0x8242, 0x04500000 / 2