That said, if you are dead-set on doing it this way, you need to give more information as to what problem you are encountering?
Starting a server on windows uses the same command line parameters as you would find on linux. Alternatively, you can even run the server via the normal dom3 game UI (tho this is not recommended as it gets a little funny when you want to play your turn). If you are looking for the command line itself, it goes something like this:
dom3 -ST -port <port here> <game name here>
Keep in mind thats all from memory tho so I could be missing something. All the game setting switches have been removed in this command line since you say you only want to run a previously made game, rather than generate a new one.