You ought to look at using a module that handles the mailing itself, and scrap the idea of using MS Outlook. What could Outlook be providing that you can't do without?

I personally have had great results with MIME::Lite. It's available via PPM, so it's easy to install. The POD for that module gives examples that are clear to follow. And in a Windows environment where you don't have sendmail, it will even handle the transport itself.