Sorry - I've been out of town for a bit, and wanted to take some care with this answer.
Microsoft Antispyware doesn't modify the network settings on a machine it is installed on. It does inquire about those settings in order to understand proxys or firewalls, but it doesn't change them.
Cleaning spyware may also disable software firewalls (on individual machines) and we've seen some instances of machines which, after cleaning of spyware, evidence symptoms of worm infections which might include the kind of traffic you mention.
So some incident of this sort could be at the root of your report--but it's hard to tell at this distance.
A network behind a firewall, and with controls in place to ensure that there are no ongoing worm infections in place shouldn't have allowed for such an infection--but this protection isn't easy to manage--all that is needed is for an infected laptop to be plugged in.
So--Netbui should not be involved here unless it is already used on your machines. Netbios--which is different, might be involved, again, if you are using it (and most people are.)--but these acronyms are incidental to the real issue which is what caused the machine to start spouting traffic.
In the end, the root cause is spyware in place which had this result.
I'm not real satisfied with this response--it might be accurate to lay the blame on Microsoft Antispyware, if, in fact, it was cleaning of spyware which caused the machine to be left in a state which had the results you mention.
The root causes, though, are the spyware in place, and the worm or virus which also needed to exist to cause the machine to malfunction.
And there's considerable speculation on my part in this answer--since the details are sketchy about both the networking enviroment involved, and the actual incident.
--
Bill,
I hope I don't sound like I'm trolling. I feel like I'm being BS'd by our network administrator and don't have the knowledge about how the antispyware interacts with the other things happening on a PC in order to know for sure.
thanks
bvd