Mail Forwarding Weirdness

Using 10.3.9 and Mail 1.3.11 on an iMac. When I forward an email to
another account in our small office, it works fine. But when I set up
a rule to automatically forward the same email, it shows up as a mime
attachment (which, by the way, I can't figure out how to open or view
on the other computer).

Is there a way to make the "rule" forward the email as if I had done
it manually, so it doesn't show up as a mime attachment?

Thanks,
Anthony