[Plugin: Google XML Sitemaps] 404 error on admin page

The Plugin Google XML Sitemaps 3.2.1 creates the xml file, but I get a page 404 when I try to open the admin page to configure it.

i.e. The error appears on the url (when logged)
http://example.com/wp-admin/options-general.php?page=google-sitemap-generator/sitemap.php

I tried to delete it and reinstall, via backend and by hand, nothing works.

Any ideas?

Using WP 285 under IIS

http://wordpress.org/extend/plugins/google-sitemap-generator/