For anyone who can make sense of it, here's the kernel panic report and the computer details
Thanks
Interval Since Last Panic Report: 696 sec
Panics Since Last Report: 2
Anonymous UUID: 61B12C68-9D1E-49D6-BA64-11E3E45810AD
Fri Oct 30 00:18:38 2009
panic(cpu 1 caller 0x00C6CD7C): "AppleAHCIPort:

opulatePRDTable [2715] status 0 segs 0 phys 0x0 : 0x0 \n"@/SourceCache/AppleAHCI/AppleAHCI-170.0.1/AppleAHCIPort.cpp:2715
Backtrace (CPU 1), Frame : Return Address (4 potential args on stack)
0x20d3bbc8 : 0x12b4c6 (0x45f91c 0x20d3bbfc 0x13355c 0x0)
0x20d3bc18 : 0xc6cd7c (0xc71f98 0xa9b 0x0 0x0)
0x20d3bc88 : 0xc705a3 (0x2b5b600 0x2b5da00 0x38ca700 0x1000)
0x20d3bcf8 : 0xc665ef (0x2b5b600 0x2b5da00 0x20d3bd28 0x42963b)
0x20d3bd38 : 0xc66fea (0x2b5b600 0x2b5da00 0x0 0xcea5b3)
0x20d3bd68 : 0xce4e50 (0x2a80f00 0x2b6c600 0x0 0x1a9ad9)
0x20d3bda8 : 0xce03cb (0x2b5ec00 0x2b15e38 0x0 0x0)
0x20d3bde8 : 0xce0f4e (0x2b66900 0x2b15e38 0x0 0x3f1571)
0x20d3be58 : 0xce67e1 (0x2b66900 0x2b15a28 0x2b5da00 0x0)
0x20d3be98 : 0xce58ba (0x2b5ec00 0x2b15a28 0x20d3beb8 0x2b5b61c)
0x20d3beb8 : 0xc6ec6a (0x2b6b500 0x2b5da00 0x0 0x0)
0x20d3bef8 : 0xc70332 (0x2b5b600 0x80 0x0 0x2a6f4f0)
0x20d3bf48 : 0xc6d4d2 (0x2b5b600 0x2bd9540 0x20d3bf78 0x136efd)
0x20d3bf68 : 0x425d58 (0x2b63fc0 0x522b60 0x20d3bfc8 0x13ec8f)
0x20d3bf98 : 0x425a3a (0x2b57180 0x511950 0x2b06000 0x429324)
0x20d3bfc8 : 0x1a14fc (0x2b57180 0x0 0x1a40b5 0x319e998)
Backtrace terminated-invalid frame pointer 0
Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.IOAHCIBlockStorage(1.2.2)@0xcde000->0xceffff
dependency: com.apple.iokit.IOAHCIFamily(1.5.0)@0xc64000
dependency: com.apple.iokit.IOStorageFamily(1.5.6)@0x6bd000
com.apple.driver.AppleAHCIPort(1.7.0)@0xc6a000->0xc75fff
dependency: com.apple.iokit.IOPCIFamily(2.6)@0x5ce000
dependency: com.apple.iokit.IOAHCIFamily(1.5.0)@0xc64000
com.apple.iokit.IOAHCIFamily(1.5.0)@0xc64000->0xc69fff
BSD process name corresponding to current thread: kernel_task
Mac OS version:
9L30
Kernel version:
Darwin Kernel Version 9.8.0: Wed Jul 15 16:55:01 PDT 2009; root:xnu-1228.15.4~1/RELEASE_I386
System model name: iMac4,1 (Mac-F42786C8)
System uptime in nanoseconds: 57046939554
unloaded kexts:
(none)
loaded kexts:
com.pctools.iantivirus.kfs 1.0.1
com.apple.driver.InternalModemSupport 2.4.0 - last loaded 26672976183
com.apple.iokit.IOBluetoothSerialManager 2.1.8f2
com.apple.filesystems.autofs 2.0.2
com.apple.driver.AppleHDAPlatformDriver 1.7.1a2
com.apple.driver.AppleHWSensor 1.9d0
com.apple.driver.AppleUpstreamUserClient 2.7.5
com.apple.driver.AppleHDAHardwareConfigDriver 1.7.1a2
com.apple.kext.ATY_Wormy 5.4.8
com.apple.driver.AppleHDA 1.7.1a2
com.apple.driver.AppleACPILPC 1.0.6
com.apple.Dont_Steal_Mac_OS_X 6.0.3
com.apple.driver.AppleGraphicsControl 2.8.15
com.apple.driver.AppleLPC 1.3.1
com.apple.ATIRadeonX1000 5.4.8
com.apple.iokit.IOFireWireIP 1.7.7
com.apple.driver.AudioIPCDriver 1.0.6
com.apple.driver.AppleIRController 113
com.apple.driver.ACPI_SMC_PlatformPlugin 3.4.0a17
com.apple.driver.AppleBacklight 1.6.0
com.apple.driver.AppleTyMCEDriver 1.0.0d28
com.apple.driver.AppleHDAController 1.7.1a2
com.apple.driver.CSRUSBBluetoothHCIController 2.1.8f2
com.apple.driver.AppleUSBHIDMouse 1.2.4b3
com.apple.driver.AppleHIDKeyboard 1.0.9b4
com.apple.driver.CSRHIDTransitionDriver 2.1.8f2
com.apple.driver.USBCameraFirmwareLoader 1.0.9
com.apple.driver.AppleUSBMergeNub 3.4.6
com.apple.iokit.IOSCSIMultimediaCommandsDevice 2.1.1
com.apple.iokit.SCSITaskUserClient 2.1.1
com.apple.driver.XsanFilter 2.7.91
com.apple.iokit.IOATAPIProtocolTransport 1.5.3
com.apple.iokit.IOAHCIBlockStorage 1.2.2
com.apple.driver.AppleAHCIPort 1.7.0
com.apple.driver.AppleIntelPIIXATA 2.0.1
com.apple.driver.AppleFWOHCI 3.9.7
com.apple.driver.AirPortBrcm43xx 365.91.19
com.apple.driver.AppleFileSystemDriver 1.1.0
com.apple.driver.AppleUSBHub 3.4.9
com.apple.iokit.IOUSBUserClient 3.4.9
com.apple.iokit.AppleYukon2 3.1.13b2
com.apple.driver.AppleUSBEHCI 3.4.6
com.apple.driver.AppleUSBUHCI 3.3.5
com.apple.driver.AppleEFINVRAM 1.2.0
com.apple.driver.AppleACPIPCI 1.2.5
com.apple.driver.AppleRTC 1.2.3
com.apple.driver.AppleHPET 1.4
com.apple.driver.ApplePCIConfigurator 1.0.4
com.apple.driver.AppleACPIButtons 1.2.5
com.apple.driver.AppleSMBIOS 1.4
com.apple.driver.AppleACPIEC 1.2.5
com.apple.driver.AppleAPIC 1.4
com.apple.security.seatbelt 107.12
com.apple.nke.applicationfirewall 1.6.77
com.apple.security.TMSafetyNet 3
com.apple.driver.AppleIntelCPUPowerManagement 76.2.0
com.apple.driver.DiskImages 199
com.apple.BootCache 30.4
com.apple.iokit.IOSerialFamily 9.4
com.apple.driver.DspFuncLib 1.7.1a2
com.apple.iokit.IOAudioFamily 1.6.9fc5
com.apple.kext.OSvKernDSPLib 1.1
com.apple.driver.IOPlatformPluginFamily 3.4.0a17
com.apple.driver.AppleSMC 2.3.1d1
com.apple.iokit.IONDRVSupport 1.7.3
com.apple.iokit.IOGraphicsFamily 1.7.3
com.apple.iokit.IOHDAFamily 1.7.1a2
com.apple.driver.AppleUSBBluetoothHCIController 2.1.8f2
com.apple.iokit.IOBluetoothFamily 2.1.8f2
com.apple.driver.AppleHIDMouse 1.2.4b3
com.apple.iokit.IOUSBHIDDriver 3.4.6
com.apple.driver.AppleUSBComposite 3.2.0
com.apple.iokit.IOSCSIBlockCommandsDevice 2.1.1
com.apple.iokit.IOBDStorageFamily 1.5
com.apple.iokit.IODVDStorageFamily 1.5
com.apple.iokit.IOCDStorageFamily 1.5
com.apple.iokit.IOSCSIArchitectureModelFamily 2.1.1
com.apple.iokit.IOAHCIFamily 1.5.0
com.apple.iokit.IOATAFamily 2.0.1
com.apple.iokit.IOFireWireFamily 3.4.9
com.apple.iokit.IO80211Family 216.1
com.apple.iokit.IONetworkingFamily 1.6.1
com.apple.iokit.IOUSBFamily 3.4.9
com.apple.driver.AppleEFIRuntime 1.2.0
com.apple.iokit.IOSMBusFamily 1.1
com.apple.iokit.IOStorageFamily 1.5.6
com.apple.iokit.IOHIDFamily 1.5.5
com.apple.driver.AppleACPIPlatform 1.2.5
com.apple.iokit.IOACPIFamily 1.2.0
com.apple.iokit.IOPCIFamily 2.6
Hardware Overview:
Model Name: iMac
Model Identifier: iMac4,1
Processor Name: Intel Core Duo
Processor Speed: 1.83 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 2 MB
Memory: 1 GB
Bus Speed: 667 MHz
Boot ROM Version: IM41.0055.B08
SMC Version (system): 1.1f5
Serial Number (system): W86101TLU2N
Hardware UUID: 00000000-0000-1000-8000-0016CB88E1A5