RSS ticker not working on 1.6.2

I'm running a Xibo 1.6.2 server on a Windows Server 2008 RC2 machine.

It runs on top of the latest XAMPP and it works just fine. Except for when I want to implement an RSS feed into a layout.
I input the feed-URL, which is "http://feeds.n24.de/n24/homepage?format=xml" in my case, number of elements on 5, set a duration and an update interval. I leave the rest as it is.

Now if I preview the layout, it doesn't show anything. It should be noted, that the Server is going through a proxy, but through an unfiltered port and it is possible to open the feed with the IE without a problem.

The Client I'm using is an Android Client which runs on version 1.4. Once I use an RSS-feed, it doesn't even download the layout. It says:
"RetrieveRemoteResourceUnagble to get: 10_53d9066310cal_7ece36c8e070820fbdf30eb10817e3d3.html"

I also tested it on a Windows Client. This one downloaded the layout, but didn't show the feed either.
Another feed didn't work either.

I presume that it is a problem with the proxy, since it doesn't even display the feed during the design preview but i can't figure out the exact problem.