This particular bug (if it is one) is not known. My range of UPnP media renderers for testing is rather limited so it may not be compatible with many renderers out there. But the TV rebooting? Wow! Did you feed it with some media format it cannot handle? It would be very great if you could use Wireshark or a similar tool to record the network communication between Windows 7 and the TV for media renderer stuff (the traffic until the file loads on the TV) in pcap format.