Is MSN trying to open my OE?

I'm no expert, so I'm guessing that MSN is the cause of the following notice
that appears every time I open Outlook Express 6:

"Windows
Installer" - This MSI must be launched through setup." I don't know what
that means, only that this when I click OK on "Setup" it sends me back to
the original notice. Although it does not interfere with my use of OE, and
drops to the taskbar, it will not go away and keeps coming back to the
screen.

I would appreciate any tips or leads on how to remove this pesky thing.

LeRoy