If you only uses MS Outlook as the email client, you won’t need the Internet Mail provider (used, for example, to Outlook Express, Incredimail, etc.). But this behavior is strange anyway…
Why don’t you move the entry for ashmaisv.exe from the StartUp itens (Windows Registry). Can you run MSConfig from the RUN window of the Start Menu? and disable it?
If not, you can look for some Startup application at this forum: http://forum.avast.com/index.php?board=1;action=display;threadid=1509. I suggest the Startup Delayer. 8)
Oh, I was almost forgotting… Why don’t you just disable the Internet Mail provider and make the changes permanent? ;D