Two MIME types must be added. For Apache, this can be done by adding to a .htaccess file. This .htaccess file can be in the server root, document root, or any directory above where the .iwml and .nut files reside.
To add the MIME types add the following entries:
AddType text/iwml iwml AddType text/acorn nut
IntraWeb 17 already runs on Apache. Full instructions coming soon. Until then you may adapt from the Microsoft IIS instructions.