Windows 7: Media center cannot setup extender

I have a PC running windows 7 and a xbox 360 setup wireless through a WRT54GS V.7 with latest firmware. I cant seem to connect media center or stream to my xbox. Every time I try to connect through media center i get an error saying cannot setup extender.I have set all the ports on my router and enable multicasting and upnp. I have also enable streaming to all devices in wmp12 and allowed my xbox in sharing.I was able connect media center to my PC with a Ethernet cable hard wired without any problems at all.

It seems to me that my router is causing the problem. but the weird thing is 3 days ago with the same hardware I was able connect to media center through vista without any problems. I am lost and out of Ideas. I would greatly appreciate any input on this issue.