kermode, i've not personally done it, but I am going to be using something to append disclaimers, and I was looking at MIMEDefang. Perhaps check out
viewtopic.php?t=3178
as a start.
technical, it looks like the issue you are having is with the disclaimermilter installation, or perhaps with using linux in general. Your forum post would be better off on a disclaimermilter forum, until you have it successfully installed. Once you have it installed and running, perhaps then you could come back to the scalix forums to get help integrating it with scalix.
Regards
Graham