Read RSS from feed not file?

Trying to modify the DeviantArt example in the SDK.

Have made an RSS feed from my website (art images) with PHP from mySQL DB. http://www.peterhammond.com/web/rss/. Going there in a browser renders an XML file with the proper info. If I copy the text from that page and paste into a file "rss.xml" and link to that in "mediarsstoolkit.brs" Here:

photolist=m.GetPhotoListFromFeed("http://www.peterhammond.com/web/rss/rss.xml") it works just fine.

trying to link directly to the RSS feed doesnt work :
photolist=m.GetPhotoListFromFeed("http://www.peterhammond.com/web/rss/")
photolist=m.GetPhotoListFromFeed("http://www.peterhammond.com/web/rss/index.php")

What am I missing? I thought i could link to a feed, not only a file thats sitting there already. Apologies if I am clueless about something, i really only know enough to modify others work.

thanks