Routine crashing - com.apple.iokit

Question

I've been having all kinds of problems, but thought I'd resolved them -- except, it appears this one.
I leave my iMac on overnight. In the mornings I'm frequently greeted by a computer that won't wake from sleep and a hard drive that's spinning hard, audibly. The log is below -- if anyone can give me some insight, I'd appreciate it!
Jon Sherman
Wed Aug 6 07:01:42 2008
Unresolved kernel trap(cpu 0): 0x300 - Data access DAR=0x0000000000000004 PC=0x00000000274FB6F8
Latest crash info for cpu 0:
Exception state (sv=0x27fa8c80)
PC=0x274FB6F8; MSR=0x00009030; DAR=0x00000004; DSISR=0x42000000; LR=0x274FB694; R1=0x27327D80; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x274FB694 0x274FB9B4 0x274FBAC8 0x000B05D4
Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.IOATABlockStorage(2.0.3)@0x274ee000->0x27500fff
dependency: com.apple.iokit.IOStorageFamily(1.5.2)@0x27491000
dependency: com.apple.iokit.IOATAFamily(1.7.3f1)@0x26b1d000
Proceeding back via exception chain:
Exception state (sv=0x27fa8c80)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x1e525a00)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)
BSD process name corresponding to current thread: kernel_task
Mac OS version:
9E17
Kernel version:
Darwin Kernel Version 9.4.0: Mon Jun 9 19:36:17 PDT 2008; root:xnu-1228.5.20~1/RELEASE_PPC
System model name: PowerMac8,1
panic(cpu 0 caller 0xFFFF0003): 0x300 - Data access
Latest stack backtrace for cpu 0:
Backtrace:
0x0009B498 0x0009BE3C 0x00029DD8 0x000AF210 0x000B2A78
Proceeding back via exception chain:
Exception state (sv=0x27fa8c80)
PC=0x274FB6F8; MSR=0x00009030; DAR=0x00000004; DSISR=0x42000000; LR=0x274FB694; R1=0x27327D80; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x274FB694 0x274FB9B4 0x274FBAC8 0x000B05D4
Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.IOATABlockStorage(2.0.3)@0x274ee000->0x27500fff
dependency: com.apple.iokit.IOStorageFamily(1.5.2)@0x27491000
dependency: com.apple.iokit.IOATAFamily(1.7.3f1)@0x26b1d000
Exception state (sv=0x1e525a00)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)
BSD process name corresponding to current thread: kernel_task

Answer 1

Okay, I'd been running fine for a few days -- to the point that I was feeling confident enough to start reinstalling stuff -- and then last night I got the black screen and the fan on high all over again. Hard restart resulted in the computer shutting itself down upon reaching the grey apple screen.
Booted in target mode and used diskwarrior to repair it. Here's the log, below.
If anyone can give me some insight as to why this keeps happening, I'd really appreciate it. Thanks!
Jon
DiskWarrior has successfully built a new optimized directory for the disk named "iPuppethead." The new directory is
ready to replace the original directory.
Notes:
The original directory is damaged and it was necessary to scavenge the directory to find file and folder data.
Some files that had been lost or thrown away may have been recovered.
Comparison of the original and replacement directories indicates that there will be changes to the number, the
contents and/or the attributes of the files and folders. It is recommended that you preview the replacement
directory and examine the items listed below. All files and folders were compared and a total of 14,480,521
comparison tests were performed.
• All errors in the directory structure such as tree depth, header node, map nodes, node size, node counts, node
links, indexes and more have been repaired.
Disk: "iPuppethead"
Repaired the Available Disk Space of the Volume Information
Repaired the Attribute Bits of the critical Volume Information
Location: "Desktop"
Folder: "tmp"
Repaired Item Count
Location: "iPuppethead/private/"
Folder: "log"
Repaired Item Count
Detected Fewer Items
Location: "iPuppethead/private/var/"
Folder: "ERO Help"
Repaired Custom Icon Flag
Location: "iPuppethead/Applications/Quicken 2007/Quicken 2007/Contents/SupportApps/Emergency Records
Organizer/Contents/Resources/"
Folder: "Hewlett-Packard"
Repaired Custom Icon Flag
Location: "iPuppethead/Library/Documentation/Help/"
Folder: "Media"
Repaired Custom Icon Flag
Location: "iPuppethead/Users/Shermania/Movies/Zach's First Movie.iMovieProject/"
File: "SpamSieve Log.log"
Detected Overlapping Contents, this file will be relocated AFTER replacing the directory
Location: "iPuppethead/Users/Shermania/Library/Logs/SpamSieve/"
File: "History.db"
Detected Overlapping Contents, this file will be relocated AFTER replacing the directory
Location: "iPuppethead/Users/Shermania/Library/Application Support/SpamSieve/"
File: "iPhoto 使用入門.pdf"
Repaired Text Encoding
Location: "iPuppethead/Library/Documentation/Applications/iPhoto/iPhoto Getting Started.app/Contents/
Resources/zh_TW.lproj/"
File: "iMovie '08 使用入門.pdf"
Repaired Text Encoding
Location: "iPuppethead/Library/Documentation/Applications/iMovie/iMovie 08 Getting Started.app/Contents/
Resources/zh_TW.lproj/"
File: "iDVD 使用入門.pdf"
Repaired Text Encoding
Location: "iPuppethead/Library/Documentation/Applications/iDVD/iDVD Getting Started.app/Contents/Resources/
zh_TW.lproj/"
File: "GarageBand 使用入門.pdf"
Repaired Text Encoding
Location: "iPuppethead/Library/Documentation/Applications/GarageBand/GarageBand Getting Started.app/
Contents/Resources/zh_TW.lproj/"
File: "iWeb 使用入門.pdf"
Repaired Text Encoding
Location: "iPuppethead/Library/Documentation/Applications/iWeb/iWeb Getting Started.app/Contents/Resources/
zh_TW.lproj/"
File: "system 2.log"
Repaired Duplicate Name
Detected that the Name changed
Location: "iPuppethead/private/var/log/"
File: "system.log.0 2.bz2"
Repaired Duplicate Name
Detected that the Name changed
Location: "iPuppethead/private/var/log/"
File: "system.log.2.bz2"
Detected this file is now Accessible
Location: "/private/var/log"
Explanations:
Accessible: These are items that had an entry in an inaccessible portion of the original directory. They are accessible
in the replacement directory.
Custom Icon Flag: Every folder has a flag that indicates whether or not it has a custom icon. Repairs ensure that the
icons of these folders will be properly displayed.
Duplicate Name: Every item within a given folder must have a unique name. Repairs ensure that these items can be
used.
Fewer Items: These folders have fewer items in the replacement directory than they had in the original directory. This
is usually the result of items being moved to the "Damaged Items" folder.
Item Count: Every folder keeps a record of the number of items that it contains. Repairs ensure that all items are
present when viewing the contents of these folders.
Name: This is text that is part of the directory information for each disk, file and folder and uniquely identifies a file
or folder within its enclosing folder.
Overlapping Contents: Overlapping files are files that occupy portions of the disk already occupied by another file.
These files will be relocated after replacing the directory. You must inspect these files to determine which of them
had been overwritten and damaged. Be aware that opening damaged files can cause the computer to crash.
Text Encoding: File and folder names are stored in Unicode characters. The text encoding value indicates the method
used to convert the file name to Unicode. Repairs prevent the name from being displayed incorrectly.
Volume Information: Every disk has information that describes its contents. Repairs prevent problems such as wasted
disk space and applications not functioning properly.
Disk Information:
Files: 561,858
Folders: 117,867
Free Space: 57.61 GB
Format: Mac OS Extended (Journaled)
Block Size: 4 K
Disk Sectors: 488,134,944
Media: AAPL Target Disk Mode
Time: 8/8/08 10:02:32 PM
DiskWarrior Version: 4.1 - RY220140