hmmm. Not sure about this one. Have you recently recieved a new dashboard update? That may be the cause.
I guess I should have asked this before, but is it the origonal disc or a backup? Or is it on the HDD?
I'm having this exact same problem, except I have the original CD. I googled the problem and other people said that it worked when they connected through a router. I have no clue why. That is what I'm going to do to try to fix this.