access denied to wins server?

On one of my DC's when I run Browser Monitor, I get a message "access
denied" when I try to get the properties of a second machine.
If I run Browser Monitor from the second machine I have a bunch of entries
like "\device\nbf.NdisWanNt unknown" and a bunch of entries in the security
log that shows event 537 and have no username, domain or workstation name
entries. I assume the two are related.
There is something wrong with this second machine's wins as that machine
can't browse others and it runs the antivirus. The AntiVirus needs to browse
to install new machines etc.
What do I try next? What access is denied that leaves the event log blank?