Are you able to view the page without the preview? You can test that by pressing 'save and publish', select tab properties and click the link-to-page link.
The reason for this question is that the preview function requires that you are logged in and that you have a user context cookie set. If you don't have this cookie you'll not be able to view the page in preview...
// ;) Kalle
" - Yeah I'd like to share your point of view, as long as it's my view too... (
http://www.d-a-d.dk/lyrics/pointofview)