If your System event log receives Event ID 8003 from Source Rdr from your BDC which believes it is the master browser on transport NetBT_xxxxx, you may have a router that is forwarding UDP broadcasts.
In Windows NT, each subnet will have a master browser. If the router(s) forward UDP broadcasts up to UDP ports 137 and 138, then the election broadcasts from one subnet are being forwarded to other subnets.
Bridges or switches between two dissimilar network segments within the same subnet can also cause this problem.
Make sure your router(s) are not forwarding UDP broadcasts and enable WINS or lmhosts for netbios name resolution.
NOTE: Switches configured for VLAN's (virtual segmentation) have to be configured on a per VLAN basis to prevent UDP broadcast propagation.
