Aprovecho tu post para aclarar un punto acerca de Sacred 1 y las partidas en red.
http://eod.su/su/readme/readme.html#3
El enlace de arriba lleva a un "Readme file" sobre Sacred 1
En la seccion Known Problems
Subseccion Other Problems
Encontramos esto:
# Problems with Dual Core Processors: Dual Core CPUs have been released after Sacred and Sacred Underworld / Sacred Gold development so that Ascaron wasn't able to make provisions for those CPU types in time. It does exist one special incompatibilty of Dual Core processors while playing Sacred Underworld / Sacred Gold in LAN mode: Users of those processors will not be able to open an own gameserver in LAN or OpenNet mode bacause that game is not displayed on other computers so that a connection will fail. That problem cannot be fixed anymore, unfortunately.
Supongo que es el motivo por el cual no puedes jugar en lan al sacred.