The Slingmedia site says an error W200 is T"here's a problem communicating with your Slingbox. Make sure the Slingbox is on and ready for Internet Viewing. Also check network cables, and confirm your router is set up correctly."
While never having experienced this exact error myself, I would suggest you start by confirming that your router has been programmed to assign a static IP address to the Slingbox's MAC ID address, and then programmed the router to forward port 5001 to that assigned static IP. Then reboot both the router and the Slingbox, then go to http://support.slingbox.com and login to your account and see if the description there of your SB shows all setup is complete. Then before returning to Austria, I would try to connect to your SB via the web browser or standalone player from a location that is OUTSIDE of your local network -- such as from a neighbor's network, or a local library, or a McDonalds (do the UK Mickey Dees have free wireless like all of the 11,000 McD's in the USA?). If it works from an external network in the UK, then it should also from Austria.