If I where u, use the recommended version of MCPC+, that is the one with the star behind it. On the moment of writing this, this is #269.
Second I don't have that error when I am making a Server of your modpack, so I assume your friend made a mistake somewhere. These are the steps how I make a server together with a modpack.
1. You copy all your mods of the pack into the mods folder that MCPC+ gives you.
2. You do the same for the configs.
3. You start the server up and there u go.
Note: I would personally always start with making the server before making the client. But that is my preference.