Problem with URLs

I'm using AS3 and pulling an xml file into flash. It does not seem to work unless I use absolutes. When I use http://www.sitesname.com/assets/flash/news.xml it will work when I load the site in a browser using www.sitesname.com but not when I load sitesname.com.

If I change the AS to http://sitesname.com/assets/flash/news.xml then the reverse is true. It will work when you type sitesname.com into a browser but not with the www.

Is there a way to get this to work if they use either www.sitesname.com or sitesname.com? Relative paths don't seem to load at all for some reason. I wouldn't worry about it, but for the fact I've had several clients experience this problem with my site.

It's odd that Relative Paths aren't working! I ran into a situation like this years ago, & I can't remember all the details, but I seem to remember that it was more of a back-end hosting setting, not ActionScript.

Thanks gotoAndCrash. I'll see if I can find something in that direction then. If anyone has additional details, please feel free to leave me a message.