Panic.log and Kernel Panic issues

Question

Can anyone help me out with deciphering this kernel panic log. I've had about 4 KP's in the last couple months. I only have one in my log because I think that is the only one I have had since I did an erase and install. I checked it in for repair at an Apple Store where they ran a high load test on it and found no hardware problems nor could they determine the source of the KP's.
I have plently of disk space and a third party graphics card bought and installed at the Apple Store. The computer was used in a professional creative environment every day, 10 hours a day for a year and a half and was rarely shut down overnight. It was pushed pretty hard, was kept in an area that allowed for dust accumulation and the area below the desk where it was kept had pretty poor air flow. It was probably moved around a bit while running. All a recipe for disaster, but I figure it's better to be up front about it's condition before one were to help me out.
Beside the couple KP's I've had, it will occasionally hang up while switching into a different user while using "Fast User Switching". Aside from distinguishing what this log might mean, I am also curious to what degree a KP can have on further corruption of data. Data corruption concerns me more than the occasional KP that would force me to revert to my last save.
Here is the log file. Any help you can give would be appreciated.
-Tim
--------begin of panic.log-----------
Sat Jul 21 14:38:32 2007
Unresolved kernel trap(cpu 1): 0x300 - Data access DAR=0x0000000000000008 PC=0x000000000053FB4C
Latest crash info for cpu 1:
Exception state (sv=0x5F6BA500)
PC=0x0053FB4C; MSR=0x00009030; DAR=0x00000008; DSISR=0x42000000; LR=0x0053FD60; R1=0x459DB900; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x0053FBF4 0x0053F9E0 0x00551658 0x0052EBC4 0x0052DE08 0x005532DC
0x0053FA90 0x0055190C 0x002D3B50 0x0003C884 0x000A9514
Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.IOFireWireFamily(2.2.5)@0x527000
Proceeding back via exception chain:
Exception state (sv=0x5F6BA500)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x5FC55000)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)
Kernel version:
Darwin Kernel Version 8.10.0: Wed May 23 16:50:59 PDT 2007; root:xnu-792.21.3~1/RELEASE_PPC
panic(cpu 1 caller 0xFFFF0003): 0x300 - Data access
Latest stack backtrace for cpu 1:
Backtrace:
0x000952D8 0x000957F0 0x00026898 0x000A8004 0x000AB980
Proceeding back via exception chain:
Exception state (sv=0x5F6BA500)
PC=0x0053FB4C; MSR=0x00009030; DAR=0x00000008; DSISR=0x42000000; LR=0x0053FD60; R1=0x459DB900; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x0053FBF4 0x0053F9E0 0x00551658 0x0052EBC4 0x0052DE08 0x005532DC
0x0053FA90 0x0055190C 0x002D3B50 0x0003C884 0x000A9514
Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.IOFireWireFamily(2.2.5)@0x527000
Exception state (sv=0x5FC55000)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)
Kernel version:
Darwin Kernel Version 8.10.0: Wed May 23 16:50:59 PDT 2007; root:xnu-792.21.3~1/RELEASE_PPC
--------end of panic.log-----------

Answer 1

Since it references com.apple.iokit.IOFireWireFamily, I suspect that some FW device is causing the panic. Disconnect all of them and see if that stops the problem. As for general KP stuff, start with http://www.thexlab.com/faqs/kernelpanics.html