XML files not working when I go to "www"

programming
1

I have some XML files that look like this:

<photo>
<content src=“http://mysite.com/slideshow/pic/1m.jpg” />
<caption><![CDATA[<head>Product Name</head>]]></caption>
<link src=“http://mysite.com/productname.php”/>
</photo>

(Note they don’t have “www”)

So, when I go to:
http://mysite.com/productname.php
(no “www”) Things work fine, but

when I go here:
http://www.mysite.com/productname.php
(with “www”) Things don’t resolve to their links.