Outlook 2003 on Windows XP Pro...

I have several macros in ThisOutlookSession that I use regularly. They are
digitally signed to me. Now I have added an Application_Startup event
handler, like this:

Private Sub Application_Startup()
MsgBox "Welcome, " & Application.GetNamespace("MAPI").CurrentUser
End Sub

It works when I run it from the editor, but it is never called on startup.

I have read several posts on this topic and tried deleting everything in
ThisOutlookSession and reloading. Any other suggestions welcome!

I had recently installed ZoneAlarm Security Suite, which has a junk-mail
filter (made by MailFrontier, I understand) with an Outlook Com addin. When
I disabled the addin my Application_Startup event handler started working.