Mediaserver stops working when starting lighttpd

I just bought a DS1513+ and installed Media Server to stream media on my Xbox One (DLNA). Everything worked fine until I install rTorrent + rUtorrent. Now every time that I start lighttpd (needed for rUtorrent), I can see my server on the Xbox One but I can't play anything (giving me an error saying to try later...). If I restart the Media Server then I can play my media on the Xbox but can't access rUtorrent anymore (need to restart lighttpd).

Any idea? It's getting very annoying... Thanks!