You will have Microsoft what the wntServerInfo function does under the covers as it relies on APIs provided by them but it is possible to get a good idea of what is happening. It is surprising your 'network groups' didn't check the firewall logs to determine the source of the problem for themselves. They would have likely found that they needed to open up at least one Netbios TCP port. The most likely candidate is port 139 but there is some chance that UPD ports 137 and 138 are required as well. They can trial-and-error for the correct ports or use Wireshark to check network traffic, if the information isn't in the logs.