Multiplayer can work, but requires some setup first.
The problem is with the current DirectPlay implementation. Read here how to set it up: http://wiki.winehq.org/DirectPlayGames
To get multiplayer working for games that use a DirectPlay version prior to 8, place the following DLLs: dplayx.dll, dpnet.dll, dpnhpast.dll and dpwsockx.dll in this archive in WINE's windows/system32 directory, then add DLL overrides (native,builtin) with WINECFG.
In case of any problems be sure to see the instructions on http://wiki.winehq.org/Infinity_Engine_Games