Media Center Extender Setup Failed at step 120

I'm trying to connect my Windows 7 RC machine to my Xbox 360 and I keep getting this error when configuring the Xbox in Windows Media Center. I've tried doing the set up a few times, removed Media Center completely and reinstalled all without any luck.

Any insight is appreciated,
E

From Media Center Error Logs:
- System

- Provider


[ Name] Microsoft-Windows-Media Center Extender


[ Guid] {7B7838A3-6562-4269-BB7A-97B0D9593882}



EventID 523


Version 0


Level 2


Task 4


Opcode 0


Keywords 0x8000000000000000

- TimeCreated


[ SystemTime] 2009-05-16T13:52:19.829101500Z



EventRecordID 173


Correlation

- Execution


[ ProcessID] 3556


[ ThreadID] 1204



Channel Media Center


Computer Grimlock

- EventData

SetupStep 120

Error -2147467259

hmmmm... in the MC options do you have to where it finds the extenders automatically, or the option to not display that it DID find extenders?

with the default settings for MC, it found my linksys extender right off the bat, punched in the code and i was on my way. Different from 7000... no auto recognition, like upnp

MC finds the Xbox automatically. I find the code on the xbox and hit next then go to MC and enter the code and hit next and then it gives the error. I can stream movies from my computer to the xbox using xbox's media browser but cannot seems to connect the extender.

when you find the code, keeping in mind i only have a media extender not an Xbox, you DONT hit next, you leave that screen with the code, to stand. Then go to your pc, fire up media center, add extender, then enter the code there, and THERE you hit next. It will then go thru connecting and configuring the pc/extender

another tidbit of info i forgot to mention that may and should help in most situations having the connection problem, tho streaming you say is fine, wich throws a wrench in my advice here. Try going into your router, and allow multicast... untick to not filter multicast on most routers. This is usually found under the security tab in the router's configuration.

still not working... I've removed all certificates and tried NOT hitting next at the key screen on the Xbox as well as hitting next. my router is wide open, but i am able to stream music and video to the xbox through the libraries, just cannot get MC to connect. Everytime it's the Setup Error at step 120, unspecified error.