2 possible solutions if you never tried these:

1.
Create a directory C:\windows\system (you might already have this directory)
Copy the files dpwsockx.dll and dpmodemx.dll from c:\windows\sysWoW64 to c:\windows\system.

Has to do with where old games end up looking for files, and I guess sysWoW64 is a place for 32 bit emulation on a 64 bit os. But they arent looking for syswow64, they are looking for system.

2. Have the required ports open. Even if playing on LAN(through a router), you probably need to open the ports to host and send data.

#1 may not even matter. It is just something I read., #2 mattered for me as I was trying to test between my desktop and laptop(desktop wired connection, laptop wireless)

If you play over internet with someone specific. Forwarding ports on each person's router is necessary as well.(me and my brother are 300 miles away)