Security Update for CAPICOM (KB931906)

I have spent three days trying to get this update to install. I have tried
atleast a half dozen times to no avail. It says that it installed and then
the little yellow shield shows up again and tells me that updates are ready
to download and install ... KB931906. This goes on forever. I have twice
installed the latest V2 or Windows Installer ... still no good. I have tried
installing both updates in safe mode. Still no good. I even uninstalled
both programs and cleaned out the hard drive and all references to KB931906
and KB893803 in the registry and then reinstalled both. No deal ... I have
contacted Support twice and they have not come up with a solution.

I finally got an error message that says: "There is a problem with this
Windows Installer package. A program run as part of the setup did not finish
as expected. Contact your support personnel or package vendor."

What is going on? Do I need to get rid of Windows Installer? Help?

I have same problem in a Windows 2000 Server Machine. It is seen as forever
loop. I installed last Windows Installer, the Redistribitable SDK, to test if
it was a false notification but trouble remains. Computer software is very
basic: SQL Server 2000. Only non standard addition is an avast! Antivirus,
server edition. All temp files were deleted, so there is no a reason for
failed process

I just ran across this problem doing a load of updating on a neglected XP machine, nothing seems to work. Did anyone find a solution?

I found this solution posted elsewhere:

Roll back XP to service pack 2 then install update. It seems to have worked so far.