Logs flooded with CGSResolveShmemReference when going from 10.5.7 to 10.5.8

Question

Could someone please explain to me what changed with respect to "CGSResolvShmemReference" between 10.5.7 and 10.5.8.
I just upgraded to 10.5.8 earlier today and applied the latest security patch and I'm getting these messages in my logs:
CGSResolveShmemReference: reference offfset (xxxx) exceeds bounds (xxxx) on shmem obj 0x<hex number>.
I'm getting this from a LOT of apps, from the Dock, iMovie, iPhoto, iShowU, Firefox, Thunderbird, Finder, VirtualBox, etc etc
I have a large memory Mac Pro config that seemed to "behave" much better with 10.5.7 (I have 13GBs of RAM). I could run 4-5 Virtualbox guest VMs, multiple browsers, do screencapture of screencasts, edit the screencasts in iMove, run different browsers and email cients, etc etc, all without my mac breaking a sweat (well at least not a heavy sweat).
Now, nothing seems to behave. iMovie is unstable, firefox will slow down and speed up, thunderbird too, iShowU will have MISSING menu lists when selecting a menu drop down, iMovie will do the same, iPhoto doesn't seem to pick up all the albums I have, at least not between invocations consistantly, and I can't do the same tasks concurrently that I used to with 10.5.7 because of little quirks as previously explained or in the case of iShowU and/or iMovie, it will just crash.
10.5.8 from my perspective is JUNK because it makes me LESS productive than 10.5.7 with all these little inconnsistant application quirks that have started since I went to 10.5.8.
Ever since I upgraded, my apps have misbehaved and my logs are inundated with these messages so I have to believe the issues are related. I really don't want to re-install from scratch JUST to get back to 10.5.7....
Could someone please expalain... and please don't pull any punches (I'm technical).
Bob

Answer 1

Of course not.  Computers always work perfectly.  Upgrades are always flawless.  User data is never lost.  Disks never fail.  Corruptions never occur.   Power is completely reliable.  :-)
But back here on Planet Earth, where bad things do occasionally happen to good data, yes, always have backups of your files.  At least the data that you care about.
The OS files?  Useful for fast(er) recoveries, but available from distributions if lost.  Those files can be recovered.  But your own unique user-local files?  Definitely have copies of those.
Somewhat more seriously, that you're even asking this question could imply you're not already running Time Machine or related archival processing; that you're not creating your own regular backups.  If that's the case, then your data is already exposed to corruption, loss, user error, and to intentional deletions that can sometimes be initiated by miscreants subsequent to a security breach.
But if you do have a Time Machine backup configured and going, you can directly trigger a backup to get the latest copies of the files (if you've been making any changes since the most recent TM backup) and allow it to run to completion, then do your upgrade.