Make sure nothing is blocking TCP port 42.
Try breaking the replication then stopping the WINS service on your PDC. Move the files from the Windows\system32\wins folder to a temp location. Restart the WINS service and the DB files will be recreated, then restart both your servers and set up the replication
You could try manually copying the files from the wins folder on the PDC to the same folder on the BDC and then force a replication.
There’s something on this page about using system monitor to report on WINS replication, it might help troubleshoot what is going on: