Hello @plc24,
sorry for the late response:
Sadly, Steam and disc version of the game are not compatible to each other.
You will never be able to see other player in the lobby if:
- You have different distributions of the game (i.e. said disc VS Steam)
- You have different files in the root directory if either EaW or FoC (this can easily happen when one player does have no or a different version of the ramfix installed)
- You have different file versions of the mod
To remedy these problems, I recommend that all players use the Compatibility Check of the launcher (you can find it in the settings). It points out all issues you might have.
Alternatively, since you are in LAN, all but one player delete their install directories (EaW and FoC the LucasArts folder) and then copy it from the remaining player. This way, you will have 100% identical files.
Furthermore make sure that you allow the game in your firewall.
Hope this helps :)