Where do I put my sitemap?

Hi,
I've created a sitemap for my website (www.jims-jaunts.co.uk) http://web.mac.com/rimmerpaula/iWeb/ using xmlsitemaps.com - http://www.xml-sitemaps.com/details-web.mac.com-rimmerpaula-iWeb.html

I've dragged & dropped it into the following location; iDisk > Web > Sites > iWeb > Jim Rimmer

I then try to add the following url to my google webmaster account; http://web.mac.com/rimmerpaula/sitemap.xml but I get this message -

General HTTP error: 404 not found
We encountered an error while trying to access your Sitemap. Please ensure your Sitemap follows our guidelines and can be accessed at the location you provided and then resubmit.

I've tried moving the site map around to different folders but I get the same message. I'm doing something wrong!

Paula 🙂