This is the fix. IF YOU ARE NOT RUNNING AN en-US LOCALE YOU MUST STOP IMMEDIATELY AND CONSULT WITH ME!
^Sorry for the shouting! Not trying to be rude!
C:\Windows\Temp\CheckSUR\winsxs\Manifests is a drop box for the System Update Readiness Tool. If we put files in there, it will use it as a source for finding good copies, and hopefully fix your issue.
NOTE: This fix was created specifically for this user! If you are not this user, do not run this fix, but instead create a new topic and you will be helped!
Download the attached Packs.zip. Inside will be two files. Put both of these files into C:\Windows\Temp\CheckSUR\winsxs\Manifests Make sure that they are extracted from the zip file. Do not try to modify them in any way. If you don't have that folder, create it.
Once both files are in there, run the System Update Readiness Tool again. Wait for it to complete.
Retry your failed update. Hopefully it will be successful.
EITHER way, failed or succeeded, upload just this small log: C:\Windows\Logs\CBS\CheckSUR.log
Upload it to this forum (NOT RapidShare) or copy and paste it inline.