AddThis

RSS Feed Empty When Accessed from Webstie

I'm trying to display my AddThis feeds (e.g. http://q.addthis.com/feeds/1.0/trending.rss?pubid=zwief&period=month) on my website. If I use a browser from my machine it almost always displays fine. If I use PHP on my local machine (i.e. file_get_contents($url)) it works great, though I have seen it come up empty a few times.

If I use the exact same code on my deployed site (http://www.findlatitudeandlongitude.com/) I get nothing. I'm stumped! file_get_contents returns an empty string.

If I use a third party feed on my site (e.g. http://s3.spotcrime.com/cache/rss/phoenix.xml) it works fine.

Any thoughts?

Thanks much,

David