Inveo Magic SEO URLs

I've gone through all the installation steps and set the appropriate file permissions but when I attempt to display the main page of the osCommerce shop I get the following:
"Forbidden, perhaps you need to change the file permissions for this document or upload an index page."
The contents of the .htaccess appear to have been generated.
Any ideas?
Mike Brogan

This usually happen when there is missing mod_rewrite on the web server.