Hello again :)
Are you actively having problems with Windows Update, or is it just the troubleshooter reporting problems? Any failing updates?
DISM is a reliable tool. You can trust it in its belief of no problems found. The troubleshooter, however, is a much more prone to the potential for mistakes because of the way it works.
But as you say, we should not write off its find as immediately invalid. All of the tools scan different areas, do different things (otherwise they wouldn't all exist). DISM has not found any corruption in the areas it has looked, but that does not mean that none exists elsewhere.
Please run the following Fix-It:
http://support.microsoft.com/kb/971058
Close the pop-up Fix-It and choose the one embedded into the article. Then run it with the
Aggressive Mode box
checked.
Then restart your computer and re-run the troubleshooter. Finally, if it proves necessary, we may backup and delete a couple of logfiles. But most important question of all, as given in first line, is Windows Update actually having a problem?
Richard