Hi Simonyoung 1984,
I don't know this related to Network Access Protection. If you read the KB article @
http://support.microsoft.com/kb/968389 it is mentioned that you need to add registry keys to enable the patch feature. Did you do the registry changes after installing the patch ?
Which OS you are running ? Make sure you all the latest patches applied on the system from
http://windowsupdate.microsoft.com Thanks
-RamaSubbu SK
Sorry! Microsoft doesn't own any liability & responsibility for any of my posting.