Windows Installer keeps flashing

[ltldj]

I'm using Windows XP with MS 2000.  Everytime I open an email in Outlook, the Windows Installer box will flash then go away until I open another message.  This didn't start to happen until I installed Avast! 4.

Has anyone else had this problem?

[Lisandro]

Did you try to repair your Microsoft Office installation?
Seems that Outlook lost something or it's not well installed.

Also, make sure the avast plugin is not disabled into MS Outlook:

Outlook 2007 > Tools > Trust center > Add-inns > Manage Disabled items.
Outlook 2003 > Help > About > Disabled items.
Outlook 2002 > Help > About Microsoft Outlook > Disabled items.
Outlook 2000 > Tools menu > Options > Other > Advanced Options > Add-In Manager.