KB839645 doesn't install online on NT4

According to the Windows Life-cycle page, for security related issues
on NT4, support ends on 31 Dec 2004. That's why I'm reposting here and
hope to get assistance other than "Update your OS".

I've had problems installing the patch KB839645 on WinNT 4.0 SP6a
Workstation (no issues on Win2K SP4 Professional and WinXP SP1 Home)
and there are still some inconsistencies to be resolved:

First off, the patch could not be installed online via Windows Update.
It failed repeatedly. I've then downloaded the patch manually and
tried to install offline. That worked but still not all is well. If I
run Windows Update again (after at least one reboot of course) ,
it still wants me to apply the patch KB839645. This is nonsense since
it's already installed and an online install fails.

How can I re-establish a consistent state?

Heinz Wehner
(Karlsruhe, Germany)