Having trouble connecting Windows Media Center to Xbox?

I'm having trouble connecting my Xbox 360 to my Windows Media Center. It tells me it can't be configured and that my router may be blocking UPNP technology. I called my internet company and tried to have them open the UPNP on the router but they sounded confused about what I was trying to do and weren't much help. I have a Speedstream router with MTS. Has anybody else run into this problem? If so how (if you did) did you resolve it?