If you are setting up NAP and have your Windows System Health Agent configured to update from Windows Update as shown below:
Your Windows Vista RTM clients will be reported as noncompliant and they will get the following error :
The Windows update Agent on this computer is not configured to synchronize with Windows Server Update Services Server. An administrator must configure the Windows Update Agent service. (0xc0ff000c)
This is because Windows Vista RTM was only compatible with WSUS. This has been changed in Windows Vista SP1 and Windows XP SP3,which are compatible with Microsoft Update, Windows Update, and Windows Server Update Service server.
You will find more information on enforcing Security updates for NAP at the link below. Thanks to Mike Burk who wrote the blog below for pointing this out, and saving me from troubleshooting this issue any further.
– Louis Hardy