Try updating the OS again and copy & paste into a reply the relevant info from /var/log/install.log and /var/log/system.log. If you sent one earlier I never got it, but there's some heavy anti-spam...

http://www.versiontracker.com/dyn/moreinfo/macosx/20346

Tryupdating saft too.. it's bitching quite a bit in your console log.

..

This one.

Also, please put your pasted data in [code] tags (the # button in Advanced editing) to make it human readable.

Anyway, I need the results from /var/log/install.log

All I see there...

You've never installed anything like RadMind or DeepFreeze, and this is your computer at home, not part of a school or job that might have locked the Mac into a kiosk-mode that always replaces any...

Please post the results of:

df

yellow% df
Filesystem 512-blocks Used Avail Capacity Mounted on
/dev/disk1s9 234419560 186771496 47136064 80% /...

/Applications/Utilities/Terminal.app

You're not out of disk space, right?

That's odd.. where are you checking to see the OS version? Please post the results of (in the Terminal.app):

sw_vers

yellow% sw_vers
ProductName: Mac OS X
ProductVersion: 10.4.6...

Doubtful.

So, this isssue is still plaguing you? If so, I suggest ditching the Dock cache and the Dock plist. Of course, be forewarned that this will reset your Dock to the defaults.
...

And if you switch to another user, can you duplicate the problem?

Do you use Dock magnification or Dock hiding?

1) The purpose of a 'test user' is to determine if this problem is system-wide, or relegated entirely to your 'normal' user.

2) What do the logs say about the Dock crash?

3) in what apps...