After 10.5.3 update, Time Machine disk getting set to read-only

Question

"The Further Adventures of Time Machine..."
Since applying the 10.5.3 update, Time Machine (or something) seems to be randomly setting my backup disk (external Western Digital "My Book Studio Edition" 500GB) to read-only which, of course, brings Time Machine backups to a halt. I can generally just restart my MacBook Pro and all is well again but then after a few more hourly backups, it will go back to read-only status again. There's a couple of things about this that are odd:
1) Even if I open "Get Info" and try to reset the permissions on the drive, I'm locked out of doing so even though I'm the admin. What's even odder (more odd?), my user and "staff" show read & write but about the user name list, it states "You can only read"!?
2) I have this disk partitioned and even the partitions are read-only. Disk Utility reports the entire disk is locked.
Like I said, this has only start happening since 10.5.3 update.
Regards,
Terry

Answer 1

Here's the latest:
Also, the time machine back up drive had been smooth sailing since I hooked it up. Never had an ounce of problems until 10.5.3.
Format is Mac OS Extended.
Thanks.
CP
Last login: Mon Jun 9 18:36:23 on ttys000
cpstaley:~ cpstaley$ ls -aleO@ /Volumes/iMac\ Back-Up
total 9008
drwxrwxr-t@ 35 root admin - 1258 Jan 3 20:22 .
com.apple.FinderInfo 32
drwxrwxrwt@ 7 root admin hidden 238 Jun 5 21:04 ..
com.apple.FinderInfo 32
-r-------- 1 root wheel - 16 Dec 31 20:43 .0011243977f4
-rw-rw-r--@ 1 cpstaley admin hidden 12292 Feb 18 21:26 .DS_Store
com.apple.FinderInfo 32
-rw-rw-rw- 1 cpstaley cpstaley - 862 Dec 31 16:12 .MaxSyncConfig
drw------- 3 root admin hidden 102 Dec 31 20:43 .Spotlight-V100
drwxrwxrwt@ 3 cpstaley admin hidden 102 Jan 3 20:22 .TemporaryItems
com.apple.FinderInfo 32
d-wx-wx-wt 2 root admin hidden 68 Jun 5 16:46 .Trashes
-rw-r--r--@ 1 cpstaley admin hidden 135038 Jan 1 20:15 .VolumeIcon.icns
com.apple.FinderInfo 32
-rw-r--r-- 1 cpstaley admin - 59078 Aug 31 2007 .VolumeIcon.icns.candybarbackup
-rw-r--r-- 1 root admin - 0 Dec 31 19:52 .com.apple.timemachine.supported
drwx------ 96 root admin - 3264 Jun 5 03:30 .fseventsd
drwxrwxr-x@ 122 root admin - 4148 Dec 31 15:49 Applications
com.apple.FinderInfo 32
drwxr-xr-x+ 3 root admin - 102 Dec 31 20:44 Backups.backupdb
0: group:everyone deny addfile,delete,add_subdirectory,deletechild,writeattr,writeextattr,chown
-rw-r--r--@ 1 root cpstaley hidden 6656 Dec 31 19:50 Desktop DB
com.apple.FinderInfo 32
-rw-r--r--@ 1 root cpstaley hidden 11522 Dec 31 19:30 Desktop DF
com.apple.FinderInfo 32
drwxrwxr-t@ 48 root admin - 1632 Dec 31 15:49 Library
com.apple.FinderInfo 32
drwxr-xr-x 2 root wheel - 68 Dec 31 15:52 Network
drwxr-xr-x 4 root wheel - 136 Nov 26 2007 System
lrwxr-xr-x 1 root admin - 60 Dec 31 19:19 User Guides And Information -> /Library/Documentation/User Guides and Information.localized
drwxrwxr-t 7 root admin - 238 Dec 31 19:34 Users
drwxrwxrwt@ 3 root admin hidden 102 Dec 31 16:33 Volumes
com.apple.FinderInfo 32
drwxr-xr-x@ 4 root admin hidden 136 Aug 30 2007 automount
com.apple.FinderInfo 32
drwxr-xr-x@ 40 root wheel hidden 1360 Nov 26 2007 bin
com.apple.FinderInfo 32
drwxrwxr-t@ 2 root admin hidden 68 Mar 22 2005 cores
com.apple.FinderInfo 32
dr-xr-xr-x 2 root wheel - 68 Dec 31 15:51 dev
lrwxr-xr-x@ 1 root admin hidden 11 Dec 31 19:19 etc -> private/etc
com.apple.FinderInfo 32
-rw-r--r--@ 1 root wheel hidden 4352200 Oct 10 2007 mach_kernel
com.apple.FinderInfo 32
drwxr-xr-x@ 6 root wheel hidden 204 Dec 31 15:51 private
com.apple.FinderInfo 32
drwxr-xr-x@ 63 root wheel hidden 2142 Dec 26 13:32 sbin
com.apple.FinderInfo 32
lrwxr-xr-x@ 1 root admin hidden 11 Dec 31 19:19 tmp -> private/tmp
com.apple.FinderInfo 32
drwxr-xr-x@ 9 root wheel - 306 Sep 10 2007 usr
com.apple.FinderInfo 32
lrwxr-xr-x@ 1 root admin hidden 11 Dec 31 19:19 var -> private/var
com.apple.FinderInfo 32