This is the Winsock 2 library and support for freeaddrinfo wasn't added until Windows XP but there is a solution. You can download a modified WS2_32.DLL from here;The procedure entry point freeaddrinfo could not be located in the dynamic link library WS2_32.DLL
You only need to extract the compiled WS2_32.DLL from the dllfiles folder, then place the DLL in the same folder as the Winbox executable. Leave the original Windows DLL alone.
Winbox now runs on Windows 2000