When opening the Helm Configuration Tool, Windows Installer keeps asking for the Helm MSI file.
This is a problem with Windows MSI on your machine. For the most part, this only seems to affect machines with MailEnable on them, although there have been exceptions.
You will need to follow this Microsoft article:
to repair your Windows MSI.
After this, you may need to reinstall Helm (the front end, not the database) as Windows Installer may have removed files specific to Helm.