Is this issue about Windows Update not working or are you having trouble with Windows Installer?
http://support.microsoft.com/kb/315353
Fix it for Windows Update: http://support.microsoft.com/mats/windows_update/
Latest version of Windows Installer here: http://support.microsoft.com/kb/942288
ESET says what exactly (exact error message)?
My windows installer is not installing updates, etc. I get a message everytime I try to install a download saying that windows installer is not working and could possibly be because of Safe Mode start up. I checked to see if "safe mode" was on during start up, but could not find anything to indicate that.
My machine is XP Pro SP3.
This seemed to have happened out of the blue. Everytime I would go to shut down, updates to install came up.
ESetNod antivirus says my system is not up to date.
Any thoughts?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic