I ran in to this problem as well when I was beta testing Vista and then when it was officially release. I called Microsoft and after 4hrs on the phone we came up with a fix. You have to edit the registry, so go to regedit.

HKey_Local_Machine\System\CurrentControlSet\Servic es\Tcpip

Highlight the Parameters folder and add a new Key.
The key has to be DWORD, name the Key ARPRetryCount, and set the value to 0.

That should get the machine connected to the domain and allow you to add all domain assets to your local security listings.

Greg