Ran into this again on a Dell Dimension 4550 I was working on. The common denominator appears to be certain older Intel NICs, or at least it has been in all the machines I've had the problem with. Adding the registry key fixed it in this case as well. If you're running into event ID 1054 in your Application event log, try the registry key addition and see if it'll fix your problem. This can also be related to other items within group policy not being applied as well, not just software deployment to computers.