https://bugs.winehq.org/show_bug.cgi?id=40247
--- Comment #4 from alexchandel@gmail.com --- I did some tracing, and it's as I feared.
The program calls Netbios() with ncb_command=0x37 and ncb_lana_num=0, then with ncb_command=0x32 and ncb_lana_num=0, then with ncb_command=0x33 and ncb_lana_num=0. This eventually calls GetIfEntry(), which calls getInterfaceEntryByName(), which calls getInterfacePhysicalByName(), which (on my machine) calls sysctl().
sysctl returns an empty MAC address for the loopback interface, and Wine zeros out the rest of it (i.e. all 12 bytes).
No windows program will ever expect the first enumerated network adapter to be the loopback interface, and some old ones are hard-coded to require that the MAC address of the first adapter be known to the program's author.
Either the loopback interface should be skipped during enumeration, or Wine should return a default MAC address instead of a zeroed MAC address.